More HOV lanes for highways

[billonlogan]

HOV lanes are fine, just don't put them on the left side of the highway. They should be located on the right side for quick easy access to exit ramps. I find especially the HOV lanes on SB 404 very dangerous with drivers crossing 3, 4, 5 lanes just to get to the exit ramp. It really slows traffic down. The time saved using HOV lanes is lost when you're stuck trying to get accross multiple lanes to the exit. I've witnessed HOV drivers stopped in live traffic at HOV exit/entry points because they only have 500 to 1000metres or so to get to the exit ramp in heavy traffic. Recently I've noticed accidents on the SB 404 because of aggressive lane changers coming off the HOV lanes. Some drivers just won't yield to HOV users and allow them to get in front, so they can get to the exit ramp.

 

[interchange42]

Exiting and merging drivers at interchanges means the right lane would be a dangerous place to put a lane meant to speed people along.

42

 

[adma]

I wish they'd restore highway chevrons...

 

[yin_yang]

Exiting and merging drivers at interchanges means the right lane would be a dangerous place to put a lane meant to speed people along.

word, as well as the total overhaul of the road rules that people are used to...the fastest lane would now be on the right?? haha doesn't make any sense. people getting into accidents because of the reasons mentioned above obviously cannot drive or they would not try to merge dangerously and crash into other cars. there must be a roadside or something for people who have trouble doing that so fast...?

 

[W. K. Lis]

Do you suffer from SOV?

Do you suffer from Single Occupancy Vehicle disorder?

This website is from Virginia uses that interesting term.

http://www.traffixonline.org/home.html

They even have TV and radio ads: http://www.traffixonline.org/ads.html

 

[Chuck]

Oddly enough, the conversion of a regular lane to an HOV lane may actually increase the overall flow of traffic on that highway. If there are 4 lanes of traffic that are essentially at a stand still right now, the number of cars passing any given point per hour is quite low. If three of those lanes continue to be gridlocked but traffic moves freely on the fourth, this actually means that the flow of cars on that stretch of highway is improved.

 

[CDL.TO]

Oddly enough, the conversion of a regular lane to an HOV lane may actually increase the overall flow of traffic on that highway. If there are 4 lanes of traffic that are essentially at a stand still right now, the number of cars passing any given point per hour is quite low. If three of those lanes continue to be gridlocked but traffic moves freely on the fourth, this actually means that the flow of cars on that stretch of highway is improved.

In practice, conversion to HOV lanes never increase the throughput of automobiles on a stretch of road. By taking away one lane that is at capacity and replacing it with one that is below capacity you're reducing throughput and causing traffic to get even worse. You could potentially increase throughput if the HOV lane was running at a high volume, but still below capacity; but in real life this has never happened.

However, what HOV lanes do have to potential of doing is increasing the throughput of individuals. You won't be moving more cars, but if the cars that do move have more people in them, then person throughput is increased,

 

[canrocks]

However, what HOV lanes do have to potential of doing is increasing the throughput of individuals. You won't be moving more cars, but if the cars that do move have more people in them, then person throughput is increased,

Amen, brotha. That's exactly what I was going to say. Who cares about the vehicle throughput? We should be focusing on people throughput. And I think this will improve greatly if they convert a lane or two of the 401 to HOV. Not only will it get more people moving in fewer cars, but it will facilitate and expedite bus travel, which will be glorious. No longer will westbound Greyhound buses have to detour up the 410 and back down the 407 to skip the Meadowvale bottleneck.

 

[Chuck]

In practice, conversion to HOV lanes never increase the throughput of automobiles on a stretch of road. By taking away one lane that is at capacity and replacing it with one that is below capacity you're reducing throughput and causing traffic to get even worse. You could potentially increase throughput if the HOV lane was running at a high volume, but still below capacity; but in real life this has never happened.

I disagree, but only for highways that are consistently bumper to bumper such as the southbound 404 or westbound Gardiner. Below is a speed vs. flow diagram for a typical freeway lane (pcphpl means passenger cars per hour per lane):

Consider a 4 lane road that is completely gridlocked in rush hour, and the typical traveling speed is 5 km/hr. As per this graph, each lane carries 600 vehicles per hour, for a total of 2400 vehicles per hour. If one lane is converted to HOV and cars travel at 80 km/hr, then the total vehicle flow increases to 3400 vehicles per hour, which comes from 3x600 + 1x1600. Naturally, this also increases the people carrying capacity of the roadway.

Obviously, this won't work on highways that are moderately congested. If the HOV lane causes traffic to slow from let's say 60 km/hr to 20 km/hr on the other three lanes, then the overall capacity will drop. For that reason, I'd love to see a trial run in which sporadic conversions to HOV lanes are implemented in known areas of congestion.

And by the way, this is all theoretical. Peak flow charts are as much based on engineering as they are on driver psychology. You'll note that slower speeds fall into the "unstable flow" half of the graph, which is essentially stop and go traffic.

Ok, geek talk is over.

 

[CDL.TO]

Chuck,

But notice what I said...

"You could potentially increase throughput if the HOV lane was running at a high volume, but still below capacity; but in real life this has never happened."

How is it that when mixed flow is essentially stopped that a sufficient number of cars could even get over to the HOV lane to have it run at an optimal capacity? You're essentially stating that under specific, perfect circumstances it could increase capacity (and I agree), but when you study actual installed HOV lanes perfection simply has never been obtained.

 

[Chuck]

Well that's the thing, it's all theoretical.