Evidence That Wider Lanes Make City Streets More Dangerous

Wider driving lanes are often thought to provide extra safety margins in a traditional street design paradigm. This may be the case for high speed and high capacity highway/expressway conditions, however, in urban commuting environments the need for a safety margin is smaller do to fewer trucks, lower speeds, and higher interactions between street users.

The truth is, wider lanes (when they aren’t necessary) are actually more dangerous than narrow lanes in many ways which we will discuss in this article.

Why Are Wide Lanes More Dangerous?

Wide lanes are typically more dangerous than narrow lanes for various reasons. Wide lanes are terrible for public safety, as well as the pedestrian environment.

Pedestrians are not safe on wider streets with higher speeds. That’s because:

  • Pedestrians are forced to walk further distances to cross the street where cars are moving too fast.
  • There is little to no room for bicycles, making it more likely for someone on a bicycle to be hit by a car.

Dewan Masud Karim was the first to present hard evidence proving this theory. He did this by reviewing a wide range of existing research as well as crash databases in two cities, taking into consideration 190 randomly selected intersections in Tokyo and 70 in Toronto.

Karim found that collision rates rose as lane widths exceeded 10.5 feet and that roads with the widest lanes (12 ft.) were associated with the highest crash rates as well as higher impact speeds.

Along with this finding, he also found that crash rates rose when lane width narrowed past 10 ft. which caused him to come to the conclusion that there’s a “sweet spot” for lane widths on city streets, between 10 and 10.5 feet.

Benefits of Narrow Lanes

A common misconception is that wider lanes are safer than narrow lanes because they ensure safe, congestion free roadways. Contrary to popular belief, narrow lanes ARE safer than wider lanes in most cases.

Benefits of narrow lanes include,

  • Shorter travel distance for pedestrians crossing the street, which reduces the risk of an accident.
  • Gives drivers a greater sense of awareness since it leaves less room for error.
  • Could provide more space for protected bicycle lanes.
  • Leaves room for wider sidewalks. Wider lanes have little to no room for pedestrians to walk on the sidewalk which is a serious hazard.
  • Could provide pedestrians with a refuge island or median.

A Change is Coming

With this emerging information, many low and middle income countries have adopted this same approach in order to err on the side of caution.

Likewise, with a rising interest in walking, cycling, and bus systems, now is the time for all counties to reassess their own standards and think more about the safety and health of their cities.

Many accidents and fatalities could be prevented if the narrowing of lanes is implemented — why isn’t everyone conforming yet?

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