As if anyone needed more evidence of why lower speed limits save lives of pedestrians, cyclists and drivers, here it is, from Bill Lindeke via Charles Marohn's Strong Towns website. He introduces the issue of the cone of vision.
Driving speed has a dramatic effect on the driver’s “cone of vision.” You can see a lot more detail at 20: people on the sidewalk, a bicyclist in the periphery, or the ‘open’ sign on a storefront. At 30 mph, the window shrinks dramatically.
The Critical Ten
He also looks at the reaction time.
“I didn’t see them” is a common refrain heard by any police officer investigating a crash. The problem is that once you hit 30+ speeds, it’s a lot more difficult to stop in time to make any difference on a potential crash.
And indeed, the differences between 20mph and 30mph are huge, almost doubling the time that it takes to think about putting on the brakes and doing it. And for those that complain about increasing drive times, Lindeke also notes that it isn't the speed limit that defines driving time; it is the delay at intersections. More at Streets MN
Where I live in Toronto, this is an ongoing discussion. When Toronto's Medical Officer of Health Dr. David McKeown recommended that speed limits be reduced to 30Km/hr (20 MPH) on residential streets to save lives back in 2012, then transportation committee head Councillor Denzil Minnan-Wong said:
Doesn’t he have better things to do than interfere in every single department and everybody else’s lives? If he wants to lower speed limits, maybe he should apply for the general manager’s job in the transportation department.
The Fords asked "why does this guy still have a job?" Now, three years later, the Fords are either out of power or in the hospital, and Denzil Minnan-Wong is deputy mayor, and a nice man, John Tory, is mayor. But if there is one thing Tory learned from the Fords, it's don't mess with drivers, they have the votes. So now there is a new, more conciliatory way to kill lower speed limits: tie it up in red tape and bureaucracy forever.
So they are now proposing that streets can be limited to 30Km/hr if it is used by less than 8,000 cars per day, if 25% of the residents agree to it, 10 per cent in the case of multifamily rental dwellings. It will take years before overworked city staff get around to it, and it will create a patchwork of different speed limits that will confuse everyone. Or as walking activist Michael Black warns in the Globe and Mail,
...doing street-by-street speed-limit changes was inefficient and could result in a mish-mash that confuses drivers and leaves pedestrians unclear how much risk is posed on any given route. And he fears the debate Thursday will pre-empt a separate push for broader-based reductions in speed limits.
Like other cities, there is a different perception of pedestrian deaths than say, murder. In Toronto there are regularly more traffic deaths than there are homicides. Kill people with guns and the crowd goes wild, but as Chris Hume put it in the Star,
If 22 seniors were murdered on the streets of the GTA during a single year, there would be outrage across the land. But when that many pedestrian seniors are killed by cars, as was the case in 2013, we wring our hands and carry on.
Since the anti-jaywalking campaigns in the twenties our streets have been given over to cars and the death of pedestrians and cyclists are thought of as either the price of modern life or their own fault for being there. Enough already.