I've read elsewhere, via HN, that speed limits are generally set to the 85th percentile of traffic speeds. So in order for a speed limit to change, you probabl

I've read elsewhere, via HN, that speed limits are generally set to the 85th percentile of traffic speeds. So in order for a speed limit to change, you probably need to show that more than 15% of drivers are speeding. You might do that by showing that this stretch of road is generating a disproportionate number of tickets. You need a critical mass to be "on the wrong side". That's how marijuana was legalized, for example. Someone has to be the seed crystal around which the critical mass can grow.