CBC Science reporter Emily Chung writes for CBC’s excellent “What On Earth?” podcast and weekly newsletter that explores environmental issues.
Last week I spoke to Dr. Chung and we pondered an interesting question~why are we not connecting the fact that slower speeds on highways and cities are also a way to cut back on greenhouse gas emissions and air pollution?
As Dr. Chung writes “According to Natural Resources Canada, driving a vehicle with an internal combustion engine at 120 km/h burns 20 per cent more fuel than driving at 100 km/h. An Ontario law that requires trucks to install technology to limit their speed to 105 km/h was estimated to have reduced greenhouse gas emissions by 4.6 megatonnes between 2009 and 2020. That’s largely because air resistance increases exponentially at higher speeds, reducing a vehicle’s fuel efficiency and generating more pollution per kilometre.”
I have already written about The Netherlands where under European law nitrogen oxide emissions must be mitigated before roads, housing and airports are built. In order to build 75,000 new dwelling units this year, the Dutch government lowered daytime highway speeds. In the Netherlands 50 kilograms of nitrogen compounds per hectare are released into the environment annually where the average in the rest of the European Union (EU) is 15 kilograms per hectare.
The EU is restricting levels of air pollutants based upon World health Organization targets, and in the Netherlands 11 percent of nitrogen compounds come from vehicular traffic. It made sense to reduce that to meet pollution targets.
It is NOT the chemical element of nitrogen that is the issue but the chemical compounds created when oxygen or hydrogen is added. As DW.com reports “Ammonia contaminates groundwater and nitrogen oxides contribute to respiratory diseases and, according to the European Environment Agency, were responsible for 68,000 premature deaths across the EU in 2016.”
I wrote about the new handbook put out by NACTO (the National Association of City Transportation Officials) that recommends the adoption of slower speeds in cities to make them less deadly and more livable. While the handbook has great data, it does not include any correlation between speed and increased emissions. The handbook does point out that 2018 data from the National Highway Traffic Safety Administration found that speed factored into 25 percent of all fatal crashes that year.
It is people like Professor Marianne Hatzopoulou, Canada research chair in Transportation and Air Quality at the University of Toronto who is leading the way in making the connection for North Americans. Dr. Hatzopoulou points out that it is not only speed that factors into nitrogen oxide emissions but speed changes in accelerating and braking.
Dr. Fred Wegman, an emeritus professor of traffic safety at Delft University of Technology is credited as a developer of the “safe systems” approach to road management and recognized as such at the 2019 International Road Safety Symposium in Vancouver.
By adopting principles aimed at recognizing the safety of all road users, The Netherlands experienced a 49 percent reduction in road fatalities.
Dr. Wegman is the person saying that while reducing road speed saves lives, politically elected officials will find reducing road speed for basic sustainability reasons would be a more palatable rationale. Tying slower vehicular driver speeds with mitigating climate change accomplishes the same goal, that of safer roads, less traffic deaths, and fewer serious injuries.
It is time for this discussion to start in North America.
Images: mprnews, nationalauditoffice