To determine the 50 best and 50 worst cities for driving, we first examined the top 500 cities with the highest number of registered vehicles. Looking then into the cities with the most available traffic data, we decided on this definitive list of 100 cities.

To make a comparable quantification of how good or bad each city is to drive, we made a three-step evaluation of the data. First, we ranked the raw data from highest to lowest value and then we awarded a standard score based on their ranking in the following manner:

A low score indicates poor driving quality for that category, with each increasing number indicating that the city is better to drive in. A score of 1 represents the worst conditions possible and 10 indicates the best. Secondly, all categories were given an overall percentage. To create a comprehensive ranking, the Final Score is a weighted average of each individual category, as follows:

Final Score (i) =30% Congestion (i) + 15% Offroad (i) + 10% Parking (i) + 15% Speed (i) + 5% Air (i)+

+5% Petrol (i) + 10% Traffic Deaths (i) + 5% Road Quality (i) + 5% Road Rage (i)

Finally, we standardized the data to have a true final score. Note that for the congestion level category we represent the actual % of congestion and for the price of gasoline and diesel we put the actual price.

The study examined several key factors in order to determine the quality of driving in the 100 cities: congestion level, public transport options, the cost of parking, the cost of petrol, air pollution, the average speed between the city centre and the international airport, road fatalities, road quality and road rage.

For the congestion level score, the data was provided primarily by the TomTom Traffic Index. For the cities not included in the TomTom index, data was provided by the city councils of the respective cities. Any traffic delays or congestion caused by temporary construction work was not taken into account for this study.

The public transport options score affects the quality of driving in a city, because if there are poor public transport alternatives then there is no other option than for people to drive their cars, leading to increased congestion, faster degradation of road quality and increased road rage. A lack of off-road alternatives also means that elderly drivers are forced to continue using their cars when it might no longer be safe, leading to more road accidents. The score was calculated based on the length of the rapid transit system and suburban railway network for each city, with more kilometres of metro rail per capita equating to a higher score. Information on the size of the networks was provided by the system operators.

The parking score was calculated based on the cost of parking for one hour. Information on parking was provided by the official parking authority of the city.

The average speed score was based on the average speed between the city centre and the international airport. The average speed was calculated for three times of the day (morning rush hour, midday and evening rush hour), and then the three scores were averaged for a final score.

The air pollution score was calculated based on data provided by the World Health Organisation’s 2016 air quality in cities database.

The petrol price score was based on information from local stations taken on August 18th 2017.

The World Health Organisation’s status report on road safety 2013 was used to calculate the road traffic injuries score for the cities.

The road quality score was based on the Travel & Tourism Competitiveness Report 2013 produced by the World Economic Forum, where citizens of each country were asked to assess the quality of the roads in their country. This is also a national score and does not account for minor differences between cities.

The road rage score was calculated based on the results of a poll conducted in each of the cities asking over 1000 drivers to rate their perception of road rage and the number of incidents witnessed in the past 12 months.