Enhancing Fire Safety Knowledge among Underwater Road Tunnel Users: A Survey in China

Abstract

In recent years, the number of underwater road tunnels in Chinese cities has increased. However, the current situation of personal fire safety literacy as it pertains to these tunnels remains unclear. To address this gap, a questionnaire survey was conducted to investigate people’s awareness of escape slides, evacuation signs, and the correct evacuation paths for fire escape. A total of 1049 respondents in Changsha, China, were surveyed, with 791 valid questionnaires collected and analyzed. The findings revealed that a significant proportion of respondents (81.80%) were unaware of the presence of escape slides in underwater road tunnels, while 87.86% could not recognize them and 93.05% could not use them. Only 42.04% of respondents could identify evacuation signs in underwater road tunnels. In the event of a fire, just half of the respondents could select the appropriate escape or evacuation path. Additionally, demographic differences among respondents also influenced their level of fire safety literacy. Based on these findings, it is recommended that the government and relevant organizations should enhance the dissemination of knowledge regarding escape slides and evacuation signs in underwater road tunnels.

1. Introduction

As of the end of 2022, there are a total of 24,850 highway tunnels in China, with a total length of 26,784 km [1]. Since 2010, China has added over 1100 km of new highway tunnels annually. China is currently the country with the largest scale, largest number, and fastest increase rate of highway tunnels in the world [2,3]. Due to the dense distribution of rivers in China, with a coastline of 18,000 km and nearly 20 large cities built along rivers and seas, China has increased the construction of underwater road tunnels to further break through the traffic constraints imposed by rivers, lakes, and seas [4]. As of the end of 2020, China has jointly built approximately 245 underwater road tunnels, such as the Shanghai Hongmei South Road Tunnel, Wuhu Chengnan River Crossing Tunnel, and Haizhuwan Tunnel [5]. Nowadays, underwater highway tunnels have become one of the main ways for cities to cross water bodies. Underwater road tunnels play an important role in the sustainability of urban transportation. However, with the rapid increase in underwater road tunnels, fires caused by vehicle failures or traffic accidents have occasionally occurred [6,7,8]. Fire is a common cause of accidental disasters in modern society that causes mass casualties and property damage [9,10,11,12,13].

Table 1. Typical underwater road tunnel fires in China in recent years.

Date	Tunnel	Cause
May 2018	Yingpanlu Tunnel, Changsha	Vehicle collision leading to fire
July 2018	Yangzijiang Tunnel, Nanjing	Vehicle self- ignition
June 2019	Changjiang Tunnel, Nanjing	Vehicle self-ignition
March 2021	Taihu Tunnel, Wuxi	Vehicle self-ignition
March 2021	Yan’an East Road Tunnel, Shnaghai	Vehicle self-ignition
July 2021	Nianjiahu Tunnel, Changsha	Vehicle self-ignition
August 2021	Changjiang Tunnel, Wuhan	Vehicle self-ignition
January 2022	Yuanjiang Tunel, Changde	Vehicle self-ignition
July 2022	Changjiang Tunnel, Shanghai	Self-ignition of large trucks
April 2022	Hongmei South Road Tunnel, Shanghai	Vehicle self-ignition

shows the cases of underwater highway tunnel fires in various cities in China in the past few years. The fire safety of underwater road tunnels has become a key issue of concern for the whole society and should be highly valued by units at all levels and by traffic management departments.

Compared with ordinary highway tunnels, underwater road tunnels are longer, deeper, and have a more closed traffic environment, increasing the difficulty of fire-fighting, evacuation, and smoke exhaust [14]. In addition, because underwater road tunnels usually bear a large amount of urban traffic demand, they also have the characteristics of periodic traffic congestion and high traffic flow [15]. About 70% of underwater highway tunnels are shield tunnels, with a small cross-section and difficult cross-channel construction [16]. This can save construction costs, improve the waterproof performance of the project, and improve evacuation efficiency and space utilization [17]. Therefore, vertical evacuation facilities (as shown in Figure 1), such as escape slides or stairs, are generally used [18]. Figure 1 also shows the two forms of escape slide entrance in highway underwater tunnels. Specifically, one form of escape door placement is to install them on the tunnel walls, aligning with the general public’s anticipation of where emergency exits should be located (see Figure 1c), as depicted by [18]. Conversely, another form involves positioning the escape doors on the tunnel floor, which, when closed, are not particularly conspicuous or easily noticeable (see Figure 1d). When a fire occurs in an underwater highway tunnel, people can enter the underground escape passage through the escape slide [19]. This escape method fully utilizes the surplus space below the lane slab in the tunnel [20]. However, the complex fire risks and special escape methods of underwater road tunnels increase the uncertainty of their fire safety.

Due to the rapid increase in the number of highway tunnels and the occurrence of catastrophic tunnel fires, many previous studies mainly focused on tunnel fire safety, especially in mountain tunnels [21,22,23,24,25,26]. However, with the increase in underwater road tunnels, their fire safety has received increasing attention from scholars. Based on the analysis of the construction and fire safety-related situation of highway tunnels, the fire safety of tunnels was studied. By analyzing major fire accidents in tunnels, the experience in dealing with tunnel fires has been summarized [27]. A prediction method for tunnel fires was established through numerical and experimental calculations [28]. By evaluating fire damage to tunnel linings, some vital experimental data for fire damage assessment of reinforced concrete tunnel linings were provided [29].

Construction technology and smoke extraction systems are the main subject matter in many studies about underwater road tunnels. The technical status of underwater road tunnels in China has been introduced in terms of smoke extraction systems in underwater road tunnel and the construction methods of tunnel engineering, such as shield tunneling, drilling and blasting, and the sinking tube method [30,31,32]. The transverse smoke exhaust system is widely used in underwater road tunnels. The above studies are mostly based on practical engineering case analysis, experimental research, and numerical simulation to research the fire safety of the tunnels’ own structure or that of ancillary facilities.

Questionnaire surveys are a very common data collection method in social science research, as they can collect data quickly and effectively [33,34]. The questionnaire survey method has previously been used in tunnel fire safety studies. For example, the evacuation behavior of crew members in the face of tunnel fires was studied using questionnaires [35,36,37]. The characteristics of the evacuation behavior of people in underwater shield tunnels under a blocked condition due to fire was discussed through comprehensive evacuation drills [35]. In Greece, an online questionnaire survey was conducted to explore the driving habits and critical safety behavior intentions of crews [36]. In Norway, a questionnaire survey was conducted to study the perceived ability and practical ability of fire rescue personnel in terms of tunnel fire safety [22]. It was found that fire rescue personnel had a high level of theoretical knowledge on emergency responses and tunnel systems, but they had little practical knowledge on tunnel fires [22]. The visual features and behaviors of drivers in underwater highway tunnels were also studied [38,39]. Nevertheless, few studies to date have focused on the fire safety literacy of underwater highway tunnel operators.

In a word, research on highway tunnel safety and evacuation has achieved a lot of results. However, there is still a gap in the research on the fire safety literacy of underwater road tunnel users. In this study, the questionnaire survey method is used to analyze the current fire safety literacy of people in underwater road tunnels. This study can provide support for improving the fire safety of underwater road tunnels. The remainder of this paper is organized as follows. The next section introduces the questionnaire design and data collection process. Then, this paper focuses on analyzing the differences in people’s fire safety literacy. Additionally, the results of this study are presented and discussed.

2. Methods

2.1. Questionnaire Design

After the outline of the questionnaire was determined, the questions were formally written. Complex terms or vague expressions were avoided in favor of concise, accessible language in the questionnaire. In addition, the necessary prompts and background information were presented in the questionnaire to help respondents understand the questions accurately. A total of 17 questions, including 12 single-choice questions, 4 multiple-choice questions, and 1 fill-in-the-blank question, were designed in the questionnaire and divided into four parts. In order to avoid behavioral bias caused by conformity mentality and fixed thinking among respondents, “uncertain” options were added to the choice of answers to the questions. When respondents answered the questions in the questionnaire, if the “uncertain” option was selected, it was deemed that the respondent had chosen a negative answer. In addition to choice questions, the questionnaire also included fill-in-the-blank questions. For instance, “Age” was set as a fill-in-the-blank question, aimed at obtaining the specific age of the respondents rather than an age range.

The first part of the questionnaire concerned the demographic variables of the respondents, including gender, age, and education level. The second part consisted of 7 single-choice questions and 3 multiple-choice questions about fire safety literacy. These questions related to people’s understanding of escape slides, evacuation signs, and four main emergency fire-fighting devices (fire extinguishers, hydrants, manual alarm buttons, and emergency telephones) that ensure fire safety in underwater road tunnels.

The third part contained two questions regarding the types of vehicles and the frequency of driving in underwater road tunnels. There were various types of vehicles to choose, such as private cars, service cars, buses or long-distance buses, trucks, or others. The frequency of passing through underwater road tunnels was set at six levels, namely 1–6 times a week or more, 1–3 times a month, 1–11 times a year, not once in over a year, and never. The fourth part was based on a specific scenario studying the evacuation psychology and behavior characteristics of people when facing an underwater road tunnel fire. Different scenarios were set up depending on whether people were upwind or downwind of the fire. These scenarios tested which choice people would make if a fire broke out in an underwater road tunnel: wait for the fire rescue in the car, drive the car back to the entrance (if the fire were ahead), drive to the exit (if the fire were behind), abandon the car and run to the tunnel entrance or exit, or follow the evacuation signs to find an escape slide. Please refer to Appendix A for the final questionnaire.

2.2. Questionnaire Implementation

Changsha is a provincial capital city in southern China with 5 underwater road tunnels. Over 300,000 vehicles pass through these underwater road tunnels every day. The broad masses of drivers and passengers in Changsha were identified as the target population for the survey. The questionnaire was mainly conducted on-site and was supplemented online. On the one hand, 150 online questionnaires were distributed using Sojump and Tencent Questionnaire, and 77 valid questionnaires were recovered, with a recovery rate of 51.33%. Valid online questionnaires accounted for 9.73% of the total valid questionnaires. On the other hand, on-site questionnaires were distributed to respondents to fill out on-site. A total of 899 questionnaires were distributed on-site, and 714 valid questionnaires were collected, with a recovery rate of 80.23%. Valid on-site questionnaires accounted for 90.27% of the total valid questionnaires. The locations of the on-site survey were mainly located in major business districts, residential areas, and blocks surrounding the tunnels in Changsha, which ensured the diversity of the sample and the reliability of the data. The survey lasted about seven months, from November 2022 to May 2023.

During the survey, respondents were told that the data would only be used for academic research and remained anonymous. All respondents were asked to provide truthful responses on a voluntary basis. Any photo material taken did not involve the personal privacy of the respondents, and the legal rights of the respondents were protected.

2.3. Descriptive Statistics

Descriptive demographic statistics of valid respondents are shown in

Table 2. Demographics of valid respondents.

Variable	Categories	Frequency	Proportion
Gender	Man	419	52.97%
	Woman	372	47.03%
Age	Under 18 years old	8	1.01%
	18–35 years old	464	58.66%
	36–55 years old	277	35.02%
	Over 55 years old	42	5.31%
Education level	Junior high school degree or below	135	17.07%
	High school or technical secondary school degree	234	29.58%
	Bachelor’s or associate degree	403	50.95%
	Master’s degree or above	19	2.40%
Types of vehicle used	Private car	405	51.20%
	Commercial car	152	19.22%
	Bus or coach	161	20.35%
	Cargo van	27	3.41%
	Other	46	5.82%
Frequency of passing through underwater road tunnels	1–6 times a week or more	197	24.91%
	1–3 times a month	167	21.11%
	1–11 times a year	181	22.88%
	Not in over a year	121	15.30%
	Never passed	125	15.80%
Have paid attention to fire and escape facilities in underwater road tunnels	Often	112	14.16%
	Occasionally	243	30.89%
	Seldom	271	34.26%
	Never	165	20.86%
Whether or not respondents have participated in fire safety training or drills	Have participated	601	75.98%
	Have not participated	190	24.02%

. Of the 791 respondents, 52.97% are male, while 47.03% are female. The male-to-female ratio is about 1.13:1. The age group is principally concentrated in the 18–55 age group, and the 18–35 age group has the highest proportion of all age groups, accounting for 58.66%. This part of the group usually has a strong observation and action ability and can respond quickly under emergencies. The education level of the respondents is mostly high school or technical secondary school degree and bachelor’s or associate degree. The proportion of the population holding a bachelor’s or associate degree is 50.95%, which is the highest proportion. The respondents have a high level of education overall.

As for the types of vehicles used to pass through underwater road tunnels, 51.20% of the respondents drive or take private cars, accounting for the highest proportion, while only 3.41% of the respondents drive or take cargo vans. Regarding the frequency of passing through underwater road tunnels, more than 45 percent of respondents pass through these tunnels at least once a month, while only 15.8 percent never pass through an underwater road tunnel. This means that most people have used underwater road tunnels. Also, this result suggests that it is particularly important to improve the fire safety literacy of people regarding tunnel fires. Furthermore, 75.98% of the participants have participated in fire safety training or fire drill, while 24.02% have not. This situation is still not satisfactory, as the coverage of fire safety training or exercises is not 90% and above.

3. Results

3.1. Awareness of Escape Methods in Underwater Road Tunnels

To evaluate the state of the respondents’ awareness of escape slides, evacuation signs, emergency fire-fighting facilities, fire safety escape psychology, and behavioral tendencies, 791 valid questionnaires were counted and analyzed. As shown in Figure 2, only 18.20% of the respondents are aware of the presence of escape slides in underwater road tunnels, and 81.80% lack this awareness. Moreover, only 12.14% of the respondents can recognize escape slides in underwater road tunnels, while 87.86% cannot. Furthermore, only 6.95% of respondents have a good command of knowledge on using escape slides, and 93.05% of respondents do not. These data show that most people are unable to recognize or use an escape slide, or they do not even know whether it is in place. Above all, it can be concluded that drivers and passengers’ awareness of escape slides in underwater road tunnels is very poor.

Among the 791 respondents, 28.12% were aware of the fire risks of underwater road tunnels, while 71.88% were unaware. As for recognizing evacuation indication signs in tunnels, only 42.04% of respondents could recognize them; this proportion was less than 50%. Toxic smoke is one of the main threats to people trapped in tunnel fires [40]. Therefore, it is important that people choose the right way to evacuate. In light of this, the evacuation psychology and behavior of our participants were not appropriate and safe. When faced with a fire that broke out in front of a vehicle in an underwater road tunnel, the escape route chosen by many respondents was the wrong one. As shown in Figure 3, 10.1% of the respondents chose to wait for fire rescue in the car. Furthermore, 14.03% chose to reverse out of the tunnel, while 20.99% chose to walk or run back to the tunnel entrance. Unfortunately, only 54.87% of the respondents chose to look for escape slides according to evacuation signs. In fact, in this situation, people should abandon the car as soon as possible to escape rather than stay in the car to wait for rescue. If trapped in the car, people should immediately break the window of the car with a sharp object, such as a fire hammer, to escape from the vehicle. Otherwise, it is likely to be engulfed by the spreading fire or life-threatening smoke from the fire. In addition, people should avoid reversing or turning around to leave the tunnel, as driving in the opposite direction may cause traffic accidents and make the order of evacuation more chaotic. Returning to the entrance will also cause a risk of fire and toxic smoke injuries.

When there was a fire behind the vehicle in an underwater road tunnel, as shown in Figure 3, only 34.64% of the respondents chose to drive out of the exit quickly or ask the driver to do so, accounting for less than 50%. A total of 9.86% of the respondents chose to wait for fire rescue in the car, while 13.78% chose to walk or run to the tunnel exit. In this situation, some people still chose to find escape slides according to evacuation signs, accounting for 41.72%. However, driving through the exit as quickly as possible should be the correct approach for people located downwind of the fire point, that is, when the fire in the tunnel occurs to their rear.

3.2. Awareness of Emergency Fire Facilities in Underwater Road Tunnels

Fire extinguishers, fire hydrants, manual alarm buttons, and emergency telephones are common emergency fire-fighting facilities in underwater road tunnels. People’s awareness of emergency fire-fighting facilities in underwater road tunnels is divided into three different levels, which are the ability to recognize them, awareness of their function, and ability to use them. On the one hand, people’s awareness of different types of emergency fire facilities is uneven. Most people are only familiar with parts of emergency fire-fighting facilities, such as fire extinguishers and hydrants. On the other hand, people usually understand that there are various emergency fire protection facilities but are not clear about their correct usage method. In other words, people can recognize them but cannot use them very well. As shown in Figure 4, the respondents in this study are most familiar with fire extinguishers, followed by fire hydrants. As for manual alarm buttons and emergency telephones, most of respondents only know of their function but cannot recognize or use them. Furthermore, there are still some people who are not familiar with these four emergency fire facilities, accounting for more than 5%.

As shown in Figure 5, only 14.16% of the respondents often pay attention to the fire or escape facilities in underwater road tunnels, while 34.26% and 20.86% rarely and never pay attention to these, respectively. As the proportion of people who rarely or never pay attention exceeds 50%, the overall situation is not optimistic. Hence, it is clear that people’s attention to the fire or escape facilities in underwater road tunnels is poor.

3.3. Differences in Participants’ Fire Safety Literacy

To further analysis the differences in our participants’ fire safety literacy, this study investigated the different effects of gender, age, education level, types of vehicles used, frequency of passing through underwater road tunnels, attention to fire and escape facilities or lack thereof, and participation or lack thereof in fire safety training or drills on fire safety in underwater road tunnels. The 791 valid data forms collected were statistically analyzed using SPSS Statistics 26.0. The χ² test was used to conduct correlation analysis of the two categorical variables, and significant correlation factors were analyzed in the form of charts. The calculation of χ² is shown in Equations (1) and (2).

$${\mathsf{\chi }}^2=\sum {\displaystyle \frac{{(f_0-f_e)}^2}{f_e}}$$

(1)

$$f_e={\displaystyle \frac{n_r\times n_c}{N}}$$

(2)

where f₀ is the observed (actual) frequency of each cell in the interaction classification table, f_e is the expected frequency corresponding to f₀ in the interaction classification table, n_r denotes the total number of rows in which each f₀ is located, n_r denotes the total number of columns in which each f₀ is located, and N denotes the total number of cases.

The degrees of freedom can be calculated as stated in Equation (3).

$$df=(r-1)\times (c-1)$$

(3)

where r and c are the number of rows and columns of the interaction classification table, respectively.

After calculating the χ² values and degrees of freedom, the p-value can be calculated by checking the χ² distribution table. The significance level was set at 0.05. If p is greater than 0.05, there is no effect between the row and column variables. If p is less than 0.05, the row and column variables are significantly correlated. The p-values for the χ² test are shown in

Table 3. p-values for the χ² test.

Awareness of Underwater Road Tunnel Escape Methods	Gender	Age	Education Level	Types of Vehicles Used	Frequency through Underwater Road Tunnels	Have Paid Attention to Fire and Escape Facilities	Whether Have Participated in Fire Safety Training or Dills
Aware of escape slide presence	0.030	0.261	0.012	0.000	0.001	0.000	0.007
Recognition of escape slide	0.261	0.411	0.360	0.056	0.005	0.000	0.000
Recognition of evacuation signs	0.001	0.472	0.058	0.000	0.057	0.000	0.000
Choice of evacuation route (Fire is ahead)	0.902	0.006	0.000	0.044	0.000	0.000	0.000
Choice of evacuation route (Fire is behind)	0.110	0.001	0.005	0.004	0.000	0.031	0.000

.

The results of the χ² test indicate that the our participants’ awareness of escape slides in underwater road tunnels is significantly correlated with six factors, which are gender, education level, types of vehicles used, frequency of passing through underwater road tunnels, attention to escape and fire-fighting facilities in the tunnel or lack thereof, and participation in fire safety training or drills or lack thereof, but not with age. People’s awareness of evacuation signs in underwater road tunnels is significantly correlated with their gender, types of vehicles used, frequency of passing through underwater road tunnels, attention to escape and fire-fighting facilities in tunnels or lack thereof, and participation in fire safety training or drills or lack thereof, but not with their age and education level. Whether people can choose an escape route if a fire breaks out in an underwater road tunnel, whether the fire is in front of or behind their vehicle, is independent of their gender but significantly correlated with the remaining six factors. Therefore, more efforts should be made to promote fire safety knowledge pertaining to underwater road tunnels to people of different genders, ages, and levels of education.

The statistical differences in people’s fire safety literacy as it pertains to underwater road tunnels divided by gender are shown in

Table 4. Statistical differences in awareness level by gender.

Awareness of Escape Methods from Underwater Road Tunnels		Gender
		Man	Woman
Aware of escape slide presence	Aware	21.00%	15.05%
	Unaware	79.00%	84.95%
Recognition of evacuation signs	Able	45.11%	33.87%
	Unable	54.89%	66.13%

. On the one hand, both men and women have poor awareness of the evacuation and escape facilities in underwater road tunnels. The proportion of men and women who are not aware of the presence of escape slides is as high as 84.95%, and the proportion of men and women who cannot recognize evacuation indication signs is more than 50%. On the other hand, compared with men, a higher proportion of women are unaware of evacuation and escape facilities in underwater road tunnels.

The statistical differences in awareness of escape methods from underwater road tunnels divided by age are shown in

Table 5. Statistical differences in awareness level by age.

Awareness of Escape Methods from Underwater Tunnels		Age
		under 18 Years Old	18–35 Years Old	36–55 Years Old	over 55 Years Old
Choice of evacuation route (fire is ahead)	Stay in the car and wait for help	12.50%	9.48%	9.39%	21.43%
	Run back to the entrance	25.00%	15.30%	12.27%	9.52%
	Back the car to the entrance	0.00%	17.03%	26.71%	30.95%
	Look for escape slide	62.50%	58.19%	51.62%	38.10%
Choice of evacuation route (fire is behind)	Stay in the car and wait for help	0.00%	9.27%	10.11%	16.67%
	Drive quickly through the exit	50.00%	31.25%	37.91%	47.62%
	Run to the exit	0.00%	12.28%	16.61%	14.29%
	Look for escape slide	50.00%	47.20%	35.38%	21.43%

. For fires in front of the vehicle, the proportion of people who choose the correct evacuation route decreases with their age. Those aged 55 and over have the lowest rate, accounting for 38.10%. For fires at the rear of the vehicle, the proportion of people aged 18 to 55 who choose the correct escape route is relatively low, and these participants tend to look for an escape slide according to the evacuation signs. However, in order to reduce the loss of life and property and increase safety, people who are located downwind of the fire should choose to quickly evacuate from the exit by car.

As shown in

Table 6. Differences in choosing the correct evacuation route according to age.

Age	Proportion of Choosing the Correct Evacuation Route
	Fire Is Ahead	Fire Is Behind	Sum
Under 18 years old	62.50%	50.00%	56.25%
18–35 years old	58.19%	31.25%	44.72%
36–55 years old	51.62%	37.91%	44.77%
Over 55 years old	38.10%	47.62%	42.86%

, respondents under the age of 18 have the highest fire safety literacy as it pertains to underwater road tunnels, reflecting their wider exposure to knowledge and the higher level of publicity and education on fire safety escape knowledge. Due to a lack of reaction and observation ability and action power, people over 55 years old have the lowest awareness of choosing the correct evacuation route in underwater road tunnels, and the participants that made the correct choice accounted for only 42.86%. This shows that the older people are, the weaker their reaction and observation ability, and the lower their underwater road tunnel fire safety literacy.

Statistical differences in respondents’ underwater road tunnel fire safety literacy in terms of education level are shown in

Table 7. Statistical differences in participants’ awareness level by education level.

Awareness of Escape Methods from Underwater Tunnels		Education Level
		Junior High School Degree or Below	High School or Technical Secondary School Degree	Bachelor’s or Associate Degree	Master’s Degree or Above
Aware of escape slide	Aware	12.59%	16.96%	19.61%	42.11%
	Unaware	87.41%	83.04%	80.39%	57.89%
Choice of evacuation route (fire is ahead)	Stay in the car and wait for help	17.78%	8.93%	7.99%	15.79%
	Run back to the entrance	8.15%	16.07%	15.50%	0.00%
	Back the car to the entrance	34.07%	22.77%	15.74%	21.05%
	Look for escape slide	40.00%	52.23%	60.77%	63.16%
Choice of evacuation route (fire is behind)	Stay in the car and wait for help	16.30%	11.16%	7.26%	5.26%
	Drive quickly through the exit	32.59%	38.39%	33.41%	31.58%
	Run to the exit	20.74%	11.61%	12.59%	15.79%
	Look for escape slide	30.37%	38.84%	46.73%	47.37%

. The proportion of people who are aware of the presence of escape slides in underwater road tunnels increases with the increase in their education level. Similarly, for fires in tunnels in front of vehicles, the percentage of people choosing the correct escape route increases with their level of education. However, for fires occurring behind vehicles, the proportion of people choosing the correct escape route does not increase with the increase in education level. The specific result is that the proportion of people with a bachelor’s degree or college degree or above that choose the correct escape route is low, while people with a high school or secondary school education have the highest level of tunnel fire safety awareness. Therefore, it is necessary to strengthen the dissemination of underwater road tunnel fire safety knowledge among people with different education levels.

According to the data in

Table 8. Differences in choosing the correct evacuation route according to education level.

Education Level	Proportion of Choosing the Correct Evacuation Route
	Fire Is Ahead	Fire Is Behind	Sum
Junior high school degree or below	40.00%	32.59%	36.30%
High school or technical secondary school degree	52.23%	38.39%	45.31%
Bachelor’s or associate degree	60.77%	33.41%	47.09%
Master’s degree or above	63.16%	31.58%	47.37%

, the higher the education level, the higher the underwater road tunnel fire safety literacy. Therefore, strengthening the popularization of and education on tunnel fire safety evacuation and escape knowledge should be focused on people with low education, at the high school or secondary school level or below, to improve their awareness of fire safety in underwater road tunnel fires.

The statistical differences in people’s underwater road tunnel fire safety literacy grouped by vehicle type are shown in

Table 9. Statistical differences in participants’ awareness level by types of vehicles used.

Awareness of Escape Methods from Underwater Tunnels		Types of Vehicles Used
		Private Car	Commercial Car	Bus or Coach	Cargo Van	Other
Aware of escape slide	Aware	21.40%	20.61%	15.50%	55.56%	10.87%
	Unaware	78.60%	79.39%	84.50%	44.44%	89.13%
Recognition of evacuation signs	Able	48.30%	51.59%	39.11%	33.33%	17.39%
	Unable	51.70%	48.50%	60.89%	66.67%	82.61%
Choice of evacuation route (fire is ahead)	Stay in the car and wait for help	6.63%	7.25%	10.33%	11.11%	13.0%
	Run back to the entrance	11.55%	12.98%	14.76%	25.93%	4.35%
	Back the car to the entrance	19.89%	19.85%	21.77%	11.11%	8.70%
	Look for escape slide	61.93%	59.92%	53.14%	51.85%	73.91%
Choice of evacuation route (fire is behind)	Stay in the car and wait for help	5.87%	9.16%	9.23%	18.52%	19.57%
	Drive quickly through the exit	35.04%	34.35%	33.95%	33.33%	10.87%
	Run to the exit	12.12%	10.69%	15.50%	7.41%	10.87%
	Look for escape slide	46.97%	45.80%	41.33%	40.74%	58.70%

. A total of 55.56% of freight vehicle drivers and passengers are aware of the presence of escape slides, accounting for the highest proportion. This shows that people that take freight vehicles have the highest awareness of escape slides in underwater road tunnels. This may be in connection to their trucking jobs, as this group of people passes through underwater road tunnels more often than the general population. As for evacuation signs in tunnels, the proportion of users of private cars or commercial cars that can recognize then is about 50%, which accounts for the highest proportion among the various types of transportation.

As shown in

Table 10. Differences in choosing the correct evacuation route according to type of vehicle used.

Types of Vehicles Used	Proportion of Choosing the Correct Evacuation Route
	Fire Is Ahead	Fire Is Behind	Sum
Private car	61.93%	35.04%	48.48%
Commercial car	59.92%	34.35%	47.14%
Bus or coach	53.14%	33.95%	43.54%
Cargo van	51.85%	33.33%	42.59%
Other	73.91%	10.87%	42.39%

, people using any type of vehicle have a low level of awareness on safe evacuation and escape routes from underwater road tunnels in case of fire, as the proportion of people who can choose the correct escape way is less than 50%. People who take buses or coaches and cargo vans have a low level of awareness of fire safety, evacuation, and escape routes from underwater road tunnels, and the proportion of people who can choose the correct escape route when a fire occurs in the tunnel is low, only about 43.54% and 42.59%, respectively.

The statistical differences in the fire safety literacy of people according to the frequency of using underwater road tunnels is shown in

Table 11. Statistical differences in participants’ awareness level by frequency of tunnel use.

Awareness of Escape Methods from Underwater Tunnels		Frequency through Underwater Road Tunnels
		1–6 Times a Week	1–3 Times a Month	1–11 Times a Year	Not in over a Year	Never Passed
Aware of escape slide	Aware	25.89%	22.75%	13.81%	14.88%	9.60%
	Unaware	74.11%	77.25%	86.19%	85.12%	90.40%
Recognition of escape slide	Able	16.75%	17.37%	7.18%	9.92%	7.20%
	Unable	83.25%	82.63%	92.82%	90.08%	92.80%
Choice of evacuation route (fire is ahead)	Stay in the car and wait for help	21.83%	8.98%	2.76%	4.96%	8.80%
	Run back to the entrance	24.87%	13.77%	14.36%	5.79%	4.80%
	Back the car to the entrance	23.86%	23.95%	19.89%	25.62%	9.60%
	Look for escape slide	29.44%	53.29%	62.98%	63.64%	76.80%
Choice of evacuation route (fire is behind)	Stay in the car and wait for help	19.80%	5.99%	4.42%	6.61%	10.40%
	Drive quickly through the exit	40.10%	35.33%	36.46%	36.36%	20.80%
	Run to the exit	17.77%	16.77%	11.60%	10.74%	9.60%
	Look for escape slide	22.34%	41.92%	47.51%	46.28%	59.20%

. The proportion of people who are aware of escape slides increases with the frequency of their passage through underwater road tunnels. However, even people who pass through underwater road tunnels almost every day have a low degree of awareness of escape slides, because only 25.89% of the respondents are aware of their presence, and only 16.75% can recognize it.

The statistical differences in respondents’ fire safety literacy as it pertains to underwater road tunnels grouped by the attention they pay to escape and fire-fighting facilities in tunnels is shown in

Table 12. Statistical differences in participants’ awareness level by concern extent.

Awareness of Escape Methods from Underwater Tunnels		Have Paid Attention to Fire and Escape Facilities
		Often	Occasionally	Seldom	Never
Aware of escape slide	Aware	34.82%	27.98%	11.44%	3.64%
	Unaware	65.18%	72.02%	88.56%	96.36%
Recognition of escape slide	Able	29.46%	18.11%	5.90%	1.82%
	Unable	70.54%	81.89%	94.10%	98.18%
Recognition of evacuation signs	Able	54.46%	53.09%	33.38%	12.73%
	Unable	45.54%	46.91%	61.62%	87.27%
Choice of evacuation route (fire is ahead)	Stay in the car and wait for help	18.75%	7.82%	8.49%	10.30%
	Run back to the entrance	13.39%	8.23%	19.56%	13.94%
	Back the car to the entrance	25.89%	16.87%	21.77%	22.42%
	Look for escape slide	41.96%	67.08%	50.18%	53.33%
Choice of evacuation route (fire is behind)	Stay in the car and wait for help	9.82%	9.05%	8.49%	13.33%
	Drive quickly through the exit	41.96%	38.27%	31.73%	29.09%
	Run to the exit	14.29%	8.64%	15.13%	18.79%
	Look for escape slide	33.93%	44.03%	44.65%	38.79%

. The more people pay attention to escape and fire-fighting facilities in tunnels, the better their awareness of escape slides and evacuation indication signs.

The statistical differences in respondents’ fire safety literacy as it pertains to underwater road tunnels grouped by whether they have participated in fire safety training or drills is shown in

Table 13. Statistical differences in participants’ awareness level by fire education.

Awareness of Escape Methods from Underwater Tunnels		Whether Respondents Have Participated in Fire Safety Training or Drills
		Have	Have Not
Aware of escape slide	Aware	20.30%	11.58%
	Unaware	79.70%	88.42%
Recognition of escape slide	Able	15.14%	2.63%
	Unable	84.86%	97.37%
Recognition of evacuation signs	Able	47.42%	15.79%
	Unable	52.58%	84.21%
Choice of evacuation route (fire is ahead)	Stay in the car and wait for help	6.99%	20.00%
	Run back to the entrance	11.81%	21.05%
	Back the car to the entrance	18.14%	30.00%
	Look for escape slide	63.06%	28.95%
Choice of evacuation route (fire is behind)	Stay in the car and wait for help	6.61%	21.58%
	Drive quickly through the exit	33.28%	38.95%
	Run to the exit	11.98%	19.47%
	Look for escape slide	48.59%	20.00%

. People who have participated in fire safety training or drills have a better awareness of escape slides than those who have not participated in them, and their recognition of evacuation signs is also higher.

As shown in

Table 14. Differences in choosing the correct evacuation route according to fire education.

Whether Respondents Have Participated in Fire Safety Training or Drills	Proportion of Choosing the Correct Evacuation Route
	Fire Is Ahead	Fire Is Behind	Sum
Have	63.06%	33.28%	48.17%
Have not	28.95%	38.95%	33.95%

, a greater proportion of respondents who have participated in fire safety training or drills chose the correct fire evacuation and escape routes and had a higher fire safety literacy as it pertains to escape routes from underwater road tunnels in case of fire.

4. Discussion

Using escape slides for safety is an important way to escape fires in underwater road tunnels. What is more, before fire vehicles and personnel arrive at the scene of the fire, trapped people need to escape by themselves. Therefore, the government and relevant units should widely popularize the knowledge of escape slides in underwater road tunnels to ensure that people can recognize and use escape slides. Traffic authorities and communication service providers can jointly send text messages to the public. Repeated broadcasts of videos featuring emergency evacuation and escape routes from underwater road tunnel fires in public places can also be used as a measure to improve the public’s tunnel fire safety literacy. Moreover, increasing the knowledge of underwater road tunnel safety evacuation and escape routes in driving school training or the driving license exam process should be considered.

The government and relevant units should increase people’s fire safety training or organize fire drills to increase the public’s experience on how to behave in an emergency escape situation when a fire breaks out. Fire units can arrange large-scale drills and issue relevant announcements to the public to invite people to participate. In addition, the news and the media can also be used to post videos of fire emergency escape drills and simulations on social media for people to learn.

A vehicle collision accident in a tunnel may lead to a fire. Transportation departments can strengthen the popularization of traffic safety knowledge and reduce the occurrence of collisions and fires.

5. Conclusions

This study conducted a questionnaire survey on the fire safety literacy of drivers and passengers in Changsha, China. In the process, 791 valid questionnaires were collected. The data were analyzed descriptively and statistically in order to evaluate the status of people’s literacy on fire safety in relation to underwater road tunnels. The results showed that most people are unaware of escape slides in underwater road tunnels. Specifically, 81.80% of respondents were unaware of their presence, while 87.86% could not recognize them, and 93.05% did not know the correct way to use them. People’s awareness of evacuation signs in underwater road tunnels is still insufficient, as only 42.04% of respondents can recognize them. Furthermore, when faced with a hypothetical fire that broke out in an underwater road tunnel, only half of the respondents were able to choose the correct escape or evacuation path. The result of the χ² test showed that age, education level, the type of vehicle used to move through underwater road tunnels, tunnel use frequency, attention paid to fire-fighting or escape facilities in tunnels, and participation in fire safety training or drills have a positive impact on the sample participants’ awareness of escape routes in underwater road tunnels. Fire safety literacy in relation to underwater road tunnels should be enhanced. The government and relevant departments should popularize the knowledge of underwater tunnel fire safety through the Internet, schools, media, and books. This article only focused on the investigation of urban underwater road tunnels. It would be recommended to conduct investigations and analyses on other types of road tunnels in the future to further enhance and improve our understanding of people’s fire safety literacy as it pertains to various types of road tunnels.