3 ms·

Why US can't simply install left turn signals onto traffic lights more widely? I noticed how few of them are there in North America.

wahern 5y ago
1) Because pedestrians walk against the signal all the same. 2) Because if it's a dedicated turn signal, you dramatically increase cross-traffic wait time. To compensate you need better signal timing to minimize the number of stops, but that tends to increase speeds, which is not good for pedestrians. If the signal isn't dedicated, it doesn't actually make it easier for the driver to see pedestrians as their attention is still split. The problem with San Francisco is its reliance on surface transportation, both cars and buses. I live in the city but I can drive downtown 2x faster in a car then if I took the bus, whether there's traffic or no traffic. And while I'd prefer to take public transit, I don't prefer spending 45m-1h in a bus (the "rapid" line) when driving only takes 20-30m. That's an additional hour out of every work day, and an hour spent sitting at that. (I wouldn't mind walking 15m to a subway that would speed me downtown, but that's just not in the cards here. They're even discussing cancelling the Geary BRT project after only building a few bulb outs and painting some lanes, which in actuality saved 10 minutes at the very best.) As a pedestrian I hate cars. However, in this city I can't only be a pedestrian. To get from one part of the city to another, I need to take surface transportation, which to be efficient needs fast, smooth flowing traffic. (And to be most time efficient for me, that means driving a car, at least to any place where there isn't a direct bus line.) Doing things correctly requires a comprehensive solution which includes building new infrastructure rather than simply tearing down old infrastructure. Unfortunately San Francisco politics is too paralyzed. One the one hand you have the people who want to tear things down--close streets, etc. On the other hand you have people who don't want anything to change. And on the third hand... well, there is no third hand.

wahern 5y ago

1) Because pedestrians walk against the signal all the same. 2) Because if it's a dedicated turn signal, you dramatically increase cross-traffic wait time. To compensate you need better signal timing to minimize the number of stops, but that tends to increase speeds, which is not good for pedestrians. If the signal isn't dedicated, it doesn't actually make it easier for the driver to see pedestrians as their attention is still split. The problem with San Francisco is its reliance on surface transportation, both cars and buses. I live in the city but I can drive downtown 2x faster in a car then if I took the bus, whether there's traffic or no traffic. And while I'd prefer to take public transit, I don't prefer spending 45m-1h in a bus (the "rapid" line) when driving only takes 20-30m. That's an additional hour out of every work day, and an hour spent sitting at that. (I wouldn't mind walking 15m to a subway that would speed me downtown, but that's just not in the cards here. They're even discussing cancelling the Geary BRT project after only building a few bulb outs and painting some lanes, which in actuality saved 10 minutes at the very best.) As a pedestrian I hate cars. However, in this city I can't only be a pedestrian. To get from one part of the city to another, I need to take surface transportation, which to be efficient needs fast, smooth flowing traffic. (And to be most time efficient for me, that means driving a car, at least to any place where there isn't a direct bus line.) Doing things correctly requires a comprehensive solution which includes building new infrastructure rather than simply tearing down old infrastructure. Unfortunately San Francisco politics is too paralyzed. One the one hand you have the people who want to tear things down--close streets, etc. On the other hand you have people who don't want anything to change. And on the third hand... well, there is no third hand.