The City of Tempe has recently proposed lowering speed limits throughout the city as part of its Vision Zero plan. This plan seeks to achieve a reduction in fatal and serious crashes.

The proposal would lower speed limits on most north Tempe arterial roads from 40 to 35 MPH with slightly lower limits on select streets in the urban core, such as taking Mill Ave down to 25 MPH.

In the southern half of the city, limits would be dropped from 45 to 40 MPH.

These proposed speed limit changes are fairly small: a five mile-per-hour reduction across the board. They could still be impactful on the overall safety.

Speed kills. While this may seem like common sense, it’s important to really consider what this means. The chance of being killed by a driver increases greatly, even when the difference in speed is relatively small.

A good illustration of this is can be found from ProPublica who made a great interactive displaying the probability of being killed by drivers at different speed levels.

Hitting a pedestrian at a slightly lower speed can drastically improve the odds they survive. A pedestrian hit by a car going 30 instead of 25 MPH is seventy percent more likely to be killed. Odds are even worse for older individuals.

Will simply lowering the speed limit be enough to alter driver behavior?

In 2017, Boston lowered speed limits from 30 to 25 MPH and found significant reductions in speeding.

It’s true that simply changing the signage to reduce speed will not be enough to alter the behavior of many drivers. The most effective way to do this, is by altering the design of our streets.

The city should seek to put in place more traffic-calming elements to ensure a real reduction in speed. Moving towards streets that work for all users and not just cars is a must.

Narrowing roads and reducing lanes would naturally cause drivers to move slower and more cautiously. It would also provide room for pedestrians and protected bike lanes.

We support lowering the speed limit throughout Tempe, with the acknowledgement that it will take more than just changing road signs to fully realize changes to driver behavior.

The city is taking public input on this. Public info sessions will be held on Wednesday, Dec. 11, from 5:30-7:30 PM; and Saturday, Dec. 14, from 9:30-11:30 AM. We encourage people to attend in support, as well as to push for changes to make our streets safer for all.

We also encourage you to take a minute to comment on the plan using Tempe’s online forum.

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