Linking Deployment Outcomes to Program Impacts for Mobile Photo Enforcement

Round 1

Reviewer 1 Report

This study investigates the effects of MPE on the duration of traffic incidents using survival analysis. The topic is interesting and the artical is easy to follow. 

The main issue with this article is that the conclusions drawn are not within a causal analysis framework. The author's approach of using two groups to compare the impact of MPE is not reasonable. Are the two groups similar in factors other than those related to MPE? In other words, are the factors influencing traffic events, apart from MPE, comparable? The author should have selected a control group with similar characteristics to MPE sites to obtain causal effects. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is very interesting - I agree that speed enforcement is critical and important, given that speed is the top risk factor.

I have no major comments on the paper. I only recommend adding Discussion section - this is a necessary part of every scientific paper, which should compare the findings with previous studies, discuss potential biases and limitations, outline further progress, etc.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

This submission documents an important topic, the effectiveness of MPE. It is reasonably well written - my comments are listed below:

Ø  Line 31 – “Red-light violations and speeding are the primary factors contributing to road collisions in the United States and Canada [1]. Research indicates that both behaviors elevate the likelihood of road collisions.”

o   Does the second sentence above add anything to the first?

Ø  You define the acronym, MPE, on lines 59, 101, 135 and I’m not sure how many more times – defining first time in text is sufficient, then you can freely use the acronym thereafter

Ø  However, as far as I can tell, you never defined what the term MPE means - you should do this at first mention in the text.

Ø  Line 139: “Ongoing public debates often revolve around concerns related to privacy, the reliability of cameras, and issues of fairness, especially when speed cameras are perceived as being misused.”

o   What are these fairness or misuse issues? These must be reconciled with the seemingly or potentially contrary notion expressed on Line 45 where you stated that “Automated enforcement, in particular, offers a solution to the equity concerns often associated with traditional, human-centered policing practices.”

Ø  Line 152: “In transportation engineering, survival analysis is frequently utilized to study the  duration of roadway incidents, such as car collisions, and their impact on traffic flow and safety.”

o   Not sure what you mean by the ‘duration’ of roadway incidents – most would presumably be a few seconds, at most – is there another way to state your point?

Ø  Line 161: “It reflects the probability that an individual incident will experience a “failure” at a precise time, given that it has survived up to that point”

o   AThis probably addresses my question immediately above so you may want to consider relocating it. However, the wording here is also throwing me off – how can an incident experience failure?  Please consider rephrasing

Ø  Line 217: “In this study, K-means clustering, a technique introduced by MacQueen in 1967, was employed to categorize the sites based on various variables: number of hours, number of visits, ratio of hours per visit, and traffic count.”

o   These variables require further explanation – number of hours of … what? And how does this differ from hours/visit? What are visits? How and where and when is traffic being counted? Per ‘visit’? per hour?

Ø  Line 510: “To summarize the results, the positive effect of the number of MPE visits is greater than that of the number of deployed MPE hours. Moreover, the ratio between MPE hours to visits has the most influence on reducing the hazard of collision occurrence.”

o   Perhaps I am misunderstanding, but… these two sentences appear to be in conflict mathematically. Specifically, based on the first sentence, I would have expected the most impactful ratio to be the inverse of what you are claiming. Please consider clarifying and/or discussing as necessary.

Ø  We go straight from Analysis & Results to Conclusions – there is no Discussion section wherein your results are contextualized within the extant literature.

The writing is generally fine, but, as I've noted above, there are places where clarification is required. I believe the submission could be improved by the review of a skilled technical editor.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

accept

Reviewer 2 Report

Thank you for the revision. I can see that the review comments were addressed and the paper quality has improved. I recommend the paper to be accepted for publication in the journal.

Reviewer 3 Report

I believe you have addressed all of my concerns.