5.1.3. Gasoline Price without Subventions

In this scenario, with the purpose of reaching a gasoline price without subventions, we assume according to [36] an annual gasoline price increase of 5% over inflation during the first eleven years between 2011 and 2022, thereafter, gasoline price remains constant until the last year of the analyzed period. Under this assumption, a 17% reduction in intensity is achieved; this reduction is calculated using a price–gasoline elasticity of −0.31 according to [43].

5.1.4. Verification and Circulation Restriction in the Main 20 Metropolitan Areas and Five Border Metropolitan Areas

The aim of this measure is the implementation of inspection and maintenance programs, with tra ffic restriction for highly-polluting vehicles in the 20 Mexican cities with the largest vehicle fleets and also in the five metropolitan zones on the United States Border. This measure consists in establishing a periodic verification of engine performance, this implies a decrease in the use of fuel due to a more efficient combustion and fewer vehicles in circulation, therefore, a decrease in tra ffic congestion and an increase in the vehicles average speed is expected. It is assumed that this measure applies to 29% of existing national vehicles, which includes 42.2% of imported used vehicles. It is also assumed that 16% of existing national vehicles, including vehicles older than 8 years and 100% of imported used vehicles introduced to the metropolitan areas involved in the program, are verified and necessarily rest one day a week [36]. Finally, it is assumed a verification annual cost per vehicle of 49 USD for verification and 58 USD for maintenance [13].

### 5.1.5. Border Environmental Customs for Vehicles

This measure aims to establish a vehicle inspection program at the border to prevent the importation of those vehicles that do not comply with the national emissions' regulation. It is assumed that, in the border states, 16% of imported used vehicles do not meet the established standards. This percentage is estimated from a study conducted by [44] which reports that 84% of the inspected vehicles (56% of the total imported vehicles) were in good physical and mechanical condition. Based on this it is inferred that the remaining 16% did not have this condition and consequently, they are the ones that would not comply with the vehicle verification proposed by this measure. Therefore, the proposed environmental customs should prevent the annual importation of that 16% of used vehicles. Finally, it is considered an annual verification cost of 98 USD per imported used vehicle [13].

### 5.1.6. Optimization of Public Transport Routes in Urban Areas

It is assumed according to [38] that the optimization of public transport routes would result, on the one hand, in a reduction of the urban bus fleet by 20% in large cities (greater than 1 million inhabitants [45]); this process begins in the second year of the period of analysis and the goal is reached gradually in the year 2030. And, on the other hand, in a reduction of public transport by 44% in medium cities (between 500 thousand and 1 million inhabitants [45]) by 2030. This reduction was taken from [46] where it is proposed that this value is feasible for this medium-sized city in Mexico.
