Why Urban Traffic Accidents Continued to Occur During Lockdown and How to Prevent Them?

[This article has been originally published in Catalan in 'Espai Salut' newsletter of Diputació de Barcelona]

In spring, we saw how mobility on our roads and in our urban areas were radically altered by the COVID-19 crisis. The lockdown, travel restrictions and the increase in teleworking during the state of emergency had all wide-ranging impacts on daily mobility. Road traffic on rural and urban roads declined between 70% and 90% during the lockdown months with respect to the levels recorded in January and February of this year. This decrease in the total number of trips had a positive repercussion on the harmful effects of road traffic, improving air quality and reducing noise pollution and the number of road accidents. However, even though we saw record declines in the number of traffic accidents, they have not disappeared altogether despite minimal mobility.

Road traffic accidents represented a global pandemic long before the current health crisis. In fact, they are the tenth leading cause of mortality in the world

Road traffic accidents represented a global pandemic long before the current health crisis. In fact, with about 1.35 million deaths per year worldwide, road traffic injuries are the tenth leading cause of mortality in the world. Pedestrians, cyclists and motorcyclists—the most vulnerable road users— account for almost half of those killed in accidents. These statistics do not include the early deaths associated with a sedentary lifestyle or attributable to the high levels of air pollution caused by motor vehicle emissions. In the highly urban context of the city of Barcelona, traffic accidents resulted in 50 deaths and 8,813 injuries in 2018 compared to 60 deaths and 11,953 injuries in 2010 and 115 deaths and 18,396 injuries in 2000. While the numbers are fortunately decreasing, the cost of mobility remains high, with too many deaths and injuries occurring every year.

What are the causes of these crashes? In addition to common factors, such as a high traffic volume, distracted drivers and alcohol use, one of the chief causes of traffic accidents is speeding. Studies of traffic accidents in urban environments have shown that 5% of all collisions and 15% of fatal accidents are caused by excess speed. Furthermore, the risk of a pedestrian being killed by a car increases gradually as a function of the posted speed limit up to 50 km/h and increases exponentially once the limit passes this threshold. The risk of death or injury is higher for children and older people because of their underdeveloped or declining motion perception abilities, respectively.

One of the chief causes of traffic accidents is speeding

How did the COVID-19 crisis affect road traffic accident rates? During the national state of emergency that lasted from March 15th to May 6th, the Spanish Directorate General of Traffic (DGT) detected a 70% drop in the number of accidents on intercity roads compared to the same period in 2019. At the same time, the case fatality rate (number of deaths per 100 casualties) increased slightly. Moreover, 30% of these accidents were caused by excess speed, an increase of 6% from the beginning of the year.

The same trend has been detected in other countries. In the United Kingdom and the United States the number of detected cases of vehicles exceeding speed limits doubled during the COVID-19 lockdown. This increase may be attributable to the low levels of traffic on city streets and interurban roads during the lockdown period. Studies have shown that empty roads increase the risk of accidents because they trigger an increase in driving speeds and a decrease in driver attention levels.

So one of the lessons learned during the lockdown has been that speed remains a problem and is one of the chief causes of collisions. The lower volume of traffic made it possible for drivers to drive faster and led, therefore, to an exponential increase in the number of accidents per kilometre driven. The evidence shows that, despite a huge drop in traffic volume, accidents did not disappear from our roads during the lockdown and that speeding was one of the chief causes of crashes.

The lower volume of traffic made it possible for drivers to drive faster during the lockdown

What are the solutions? One common measure used by road transport authorities to increase safety on the roads is speed restriction. The objective of these measures is to improve road safety by limiting driving speed, with the ultimate aim of reducing the number of deaths and accidents, minimising accident severity and improving users’ perception of safety. In some cases, these measures can have other positive public health outcomes. They increase physical activity levels in the population because they facilitate walking, cycling and outdoor play. They also improve the users’ perceptions of the urban setting because they reduce noise levels and enhance air quality and individual quality of life.

In general, two types of interventions are used to restrict speed in urban areas. One strategy is traffic calming, that is, physical design and other measures put in place to slow down traffic in restricted speed zones. These measures include road narrowing and the creation of speed bumps, rumble strips, median islands and chicane curves. In other areas, speed limits are posted but no physical design measures are put in place to ensure compliance. Many examples of both types of interventions have been successfully implemented in our urban areas for many years: 30 km/h zones, 20 km/h zones, 20 km/h lanes, and formal shared streets.

The 30 km/h speed limit is outdated and more severe restrictions should be implemented, for example applying a 20 km/h limit and extending this limit to all city streets

However, although the number of collisions and casualties has been reduced, accidents and fatalities have not completely disappeared. One of the reasons for the continuing trickle of accidents is that traffic calming measures are usually implemented on narrow streets in non-central areas of our cities—zones already characterised by low traffic volume—where they are easy to apply because they do not interfere with the "desired" speed of drivers. If the goal of road safety interventions is to reduce the number of deaths and injuries to zero, it could be said that the 30 km/h speed limit is outdated and that more severe restrictions should be implemented, for example applying a 20 km/h limit and extending this limit to all city streets. Why do we have to cross a city at 30 or 50 km/h? Don’t we get there just the same driving at 20 km/h? Should people living in city centres have to tolerate traffic moving at these speeds when they walk out the door?

In fact, if we slowed down cars and motorcycles, we would encourage the use of public means of transport, such as buses and metro, because these would become more attractive. The added advantage would be that slower vehicular traffic would mean that streets could be shared safely with pedestrians, cyclists and the newly arrived electric scooters . Sharing roads and public spaces at low speeds is even more important in the current context of the COVID-19 crisis, during which the space assigned to pedestrians and cyclists has been increased to facilitate physical distancing. Apart from reducing the risk of accidents, this strategy strengthens the model of sustainable and healthy mobility. Consequently, limiting traffic speed can only be a win-win strategy.