Are Variable Speed Limits the Wave of the Future?
 

This really seems like a cost effective way to reduce stop & go traffic on congested roads. I've only seen variable limits on the NJ Turnpike, but not sure if they use it to reduce congestion or just for construction/accidents?

Just love the "Slow Down to Get There Faster" slogan. Maybe some of those impatient drivers out there will finally start to realize they ARE the root of the problem.

Atlanta getting variable speed limits this fall | Fox News

We've always had variable speed limits on every road via the adjust your speed for conditions laws. But this way everyone gets on the same page.

Nope. I was on track to be 10 minutes early to work this morning and got there 30 minutes late. Why? Because going straight on a bridge is too hard for some people to manage. It was worse than a 40 minute delay for way more people because they're too stupid to understand the traffic pattern that they drive through every day. I spent a lot of time stopped (with the engine off), but also spent a ridiculous amount of time idling in 1st gear past the stopped cars in the other lane. There was room for them to move over, but even watching us go by they still believed that their lane was the one to be in! I only saw two cars change lanes in a couple miles.

But really, variable speed limits won't work because speed limits themselves are stupid and are completely disconnected from safety. We'd need to convince people that this time, on this road, it's different. Get off this road any they're all irrational, based on focus groups, horoscopes and weather data. But here, we swear, it's based on road design, weather and traffic conditions. Honest.

http://www.caldrive.com/images/limit65.gif http://3.bp.blogspot.com/_Kom-mudcX5...s320/nad23.jpg http://wac.450f.edgecastcdn.net/8045...ad-260x300.png

When I drove on Michigan highways 8 years ago, I think it was 65-60-55 on 3 lane Interstates, with trucks prohibited from the left (65) lane. I actually liked it until one night when a bike blew past me at what had to be 160 MPH. Talk about the doppler effect!

regards
Mech

Hate to burst your bubble, but per the article, the problem (got a mirror handy?) is speed variance. Which means that people going slower than the limit are just as much a cause of congestion (if not more so) as people going faster than the limit.

Which means that it's likely going to work well if they also have, and enforce, adjustable minimum speeds. Which is only logical: if everyone travels at a uniform 70 mph, the road will handle twice as many vehicles per hour than if everyone does 35.

The main argument is that people trying to go faster than the flow of traffic disrupt the flow more than the slowpokes, who on congested roads tend to be trying to deal with exits and whatnot.

People slowing from the speed limit to deal with ramp traffic wouldn't be all that variant if other people weren't trying to do 80 through the mob.

In DC, NOVA and MD you have many roads with digital speed limit signs that are changed frequently.

Of course the speed is the max allowed and you can always go slower. :thumbup:

In Seattle we already have these.

In my experience, they do help to reduce accidents due to traffic congestion and limited visibility (they are placed on the rolling hills you drive on as you enter the city from the south on I-5). But, I have seen no effect of reduced congestion at all. And if we didn't have limited visibility in the area where traffic goes from high speed to a snarled mess, I don't think we would see any benefit at all.

We have them in Columbus, Ohio.

It makes sense, but at the end of the day, we have too many people and too poorly designed road ways. Heading west from Cleveland, a three lane highway has one exit that no one uses (turning it into two lanes) about 500 feet after a major ramp, that all the cars from the south are coming from. Here's a map:

https://lh6.googleusercontent.com/-8...5.51.42+PM.png

Heading west on 480, 71 exits onto it, and then it drops to two lanes. C'mon son. It's idiotic.

How many people would actually slow down, anyway? Speed limits around here are 65mph and NO ONE drives that speed. Changing the sign won't do anything because they are all ignored anyway.