Should the speed limit on arterial roads increase?
An arterial road in China. Photo by Saad.Akhtar.

An arterial road in China. Photo by Saad.Akhtar.

One of the most controversial issues on the agenda of the City Council of Porto Alegre, Brazil, was discussed last week at a roundtable debate and broadcast over local radio: proposed changes to the speed limit on arterial roads in the state capital. For non-experts, arterial roads are high-capacity thoroughfares which connect urban centers to freeways and other cities.

Set by the Brazilian Traffic Code at 60 km/h (37 mph), this limit came into question when, in 2010, Councilman Alcaeus Brasinha joined an initiative to raise the speed limit to 70 km/h (43 mph). The main reason for this would be a possible improvement of the flow of vehicles on the main roads of the city. Since then, the proposal has been pending in the Federal Chamber of Deputies.

However, a new proposal, from Councilmember Marcelo Sgarbossa, has been submitted, which calls for a reduction in speed limit to 50 km/h (30 mph) for light vehicles and 40 km/h (25 mph) for heavy vehicles.

Last week’s on-air discussion also featured Professor John Fortini Albano, transportation expert, and Daniel Denardi, advisor to the management of the Porto Alegre Public Transportation and Circulation, company.

While Councilman Brasinha’s proposal to raise the speed limit is based on examples from other Brazilian cities, such as Florianopolis and Rio de Janeiro, where speed limits on main avenues, such as Copacabana and Seaside North is already at 70 km/h, Councilman Sgarbossa shows that, along a 5-kilometer stretch of road, driving  60 km/h instead of 50 km/h results in a time savings of only 39 seconds. Sgarbossa also relies on recommendations from the World Health Organization, which suggests a maximum speed limit of 50 km/h in urban areas.

Slower speeds require less distance for drivers to come to a complete stop after hitting the brakes — thereby allowing more space and time to avoid a potential collision. A Belgian road safety study estimated that 45% of pedestrians die when hit by vehicles traveling at 50 km/h (30 mph), whereas the fatality rate drops to 5% when the car is moving at 30 km/h (20 mph). Furthermore, when speed limits are reduced from 50 to 30 km/h, the rate of traffic accidents decreases by around 20%.

Check out the video below that talks about the difference that 5 km/h can make:

During the broadcast, a poll was conducted, which revealed that among local listeners in Porto Alegre,  47% were in favor of increasing the speed limit, 33% for maintaining current regulations, and 20% calling for a decrease.

Where do you stand on the issue?

Originally posted on TheCityFix Brasil.

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