Not all negative impacts caused by speed can be immediately translated into twisted metal and loss of human life – a silent, lesser-known toll falls on our environment and health: impact of CO2 emissions.
Think about this way: in the average car, gasoline consumption increases by 25 per cent when the speed limit on expressways rises from 88 km/h to 112 km/h. As a result of a higher speed, NOx emissions also start to increase at 77 km/h and carbon monoxide emissions start to increase at 88 km/h, according to the National Highway Traffic Safety Administration (NHTSA).
More alarmingly, transport is the only sector whose greenhouse emissions increased between 1990 and 2008. Overall transport-based GHG output rose 25 per cent in 32 European Union countries (excluding international maritime and aviation sectors), accounting for 19.5 per cent of total emissions. CO2 is the main component of transport greenhouse gas emissions (99 per cent) and road transport is, in turn, the largest contributor to these emissions (around 94 per cent in 2008), thus accounting for 18.2 per cent of total emissions.
Despite the impact of speed-based emissions, many jurisdictions around the world, including some U.S. states, have instead raised their highway speed limit – with expected negative effects.
In Wyoming, where the speed limit was raised from 104 km/h to 120 km/h, the Environmental Protection Agency (EPA) anticipates that NOX emissions will increase by 22 per cent, CO2 emissions by 17 per cent, and VOC emissions by 6 per cent. In Delaware, where the speed limit was raised from 88 km/h to 104 km/h, NOX is expected to increase by 1 per cent, CO2 by 1 per cent, and VOC by 3 per cent, respectively. In the United States overall, changes in speed limits will result in a 6 per cent increase in NOX, a 7 per cent increase in CO2, and a 2 per cent increase in VOC. Keep in mind, this is excluding older and heavy-duty diesel vehicles, which emit significantly more particles than gasoline vehicles. While there are no precise estimates on particle emissions, the EPA maintains that such emissions will rise as speed is increased.
Cutting motorway speed limits naturally has its benefits to fuel consumption as well. Reducing speeds from 120 to 110 km/h could deliver fuel savings for current passenger cars of 12–18 per cent, assuming smooth driving and 100 per cent compliance with speed limits. In more realistic terms however, relaxing savings would be closer to 2–3 per cent on average.
Fortunately, Viion provides different types of automated speed enforcement solutions, such as the TrafficCam and TrafficCam 3D, depending on the application, location and size of deployment. The impact of reducing speed by just 10 km/h is still profound; for example, decreasing speed from 90 km/h to 80 km/h results in a reduction of 700 grams per kilometer of CO2 emissions, or 21 per cent.
In addition to reducing speed in jurisdictions world-wide, our traffic cameras can also provide vital traffic data and metrics to local transport authorities that seek to modernize their cities and reduce air pollution.