TOLLROADSnews: HNTB exec makes sharp case for toll managed lanes

[cpzilliacus]

HNTB exec makes sharp case for toll managed lanes

Matthew Click southeast division director for tolls for HNTB has written the most powerful case we've seen for toll lanes.  It's short but sharp. Toll managed lanes he says are really the only feasible way that major urban areas can come to grips with the costs of congestion. Building extra free lanes will not relieve much congestion because latent demand in peak hours soon overloads them. So there's congestion in more lanes in rush hours.

Or the extra free capacity will see the congested period slightly compressed but not seriously reduced. More transit even if successful in attracting patronage by taking drivers out of their cars is another ineffectual policy, Click notes. Like adding free lanes leaving more roadspace with diversion to transit will leave latent demand that remains to be satisfied still congesting the free lanes.

He adds: "The only strategy that can solve for congestion is an operational strategy using the congestion pricing concept with deployment strategies like priced managed lanes. Not only do priced managed lanes provide a mobility option for automobile customers, they also provide a reliable transit corridor for buses at a much lower cost than traditional fixed-rail transit."

[NE2]

holy crap induced demand

[Alps]

More complex than that, NE2. "Latent demand" also includes demand that can't be served during peak hours due to queuing. If your capacity is 6800 and you have 7500 vehicles trying to push through in an hour, you'll get 700 vehicles queued at the end of the hour (more, really, because breakdown flow has a lower capacity). Open up a new lane, suddenly instead of 6800 your volumes "magically" jump to 7500. Then you have vehicles on parallel routes getting around the 700-vehicle backup that see the new capacity open and think, "well as long as that's moving, it'll be faster." That can be another 1000 vehicles easily, and suddenly you've just eaten up everything you opened - without one new vehicle in the system.

[jeffandnicole]

More complex than that, NE2. "Latent demand" also includes demand that can't be served during peak hours due to queuing. If your capacity is 6800 and you have 7500 vehicles trying to push through in an hour, you'll get 700 vehicles queued at the end of the hour (more, really, because breakdown flow has a lower capacity). Open up a new lane, suddenly instead of 6800 your volumes "magically" jump to 7500. Then you have vehicles on parallel routes getting around the 700-vehicle backup that see the new capacity open and think, "well as long as that's moving, it'll be faster." That can be another 1000 vehicles easily, and suddenly you've just eaten up everything you opened - without one new vehicle in the system.

While true, an important thign to look at is where those additional 1,000 vehicles came from.  If they were on local residential streets, the quality of life improved for those residents and locals that now don't have congestion at their front door.  It makes getting around for local needs, such as schools, localized travel, and even walking - safer.  Since many mass-transit buses use local roads, those systems can operate at a better pace as well. 

[cpzilliacus]

More complex than that, NE2. "Latent demand" also includes demand that can't be served during peak hours due to queuing. If your capacity is 6800 and you have 7500 vehicles trying to push through in an hour, you'll get 700 vehicles queued at the end of the hour (more, really, because breakdown flow has a lower capacity). Open up a new lane, suddenly instead of 6800 your volumes "magically" jump to 7500. Then you have vehicles on parallel routes getting around the 700-vehicle backup that see the new capacity open and think, "well as long as that's moving, it'll be faster." That can be another 1000 vehicles easily, and suddenly you've just eaten up everything you opened - without one new vehicle in the system.

Absolutely correct.

But keep in mind that "magic" increase in traffic may also be trips that were being made on lower functional class roads, where they are less desirable for an assortment of reasons.

In other words, attracting vehicle trips (especially long trip length vehicle trips) to a freeway is a good thing.

[Brandon]

More complex than that, NE2. "Latent demand" also includes demand that can't be served during peak hours due to queuing. If your capacity is 6800 and you have 7500 vehicles trying to push through in an hour, you'll get 700 vehicles queued at the end of the hour (more, really, because breakdown flow has a lower capacity). Open up a new lane, suddenly instead of 6800 your volumes "magically" jump to 7500. Then you have vehicles on parallel routes getting around the 700-vehicle backup that see the new capacity open and think, "well as long as that's moving, it'll be faster." That can be another 1000 vehicles easily, and suddenly you've just eaten up everything you opened - without one new vehicle in the system.

Absolutely correct.

But keep in mind that "magic" increase in traffic may also be trips that were being made on lower functional class roads, where they are less desirable for an assortment of reasons.

In other words, attracting vehicle trips (especially long trip length vehicle trips) to a freeway is a good thing.

For many reasons,

1. Reduction in emissions.  The more vehicles idle at signals, the more emissions they spew.
2. Vehicular safety.  Freeways are the safest type of road there is.  No intersections, no cross traffic.
3. Separation of transportation types.  Pedestrian safety is improved on surface streets by moving most potential conflicting vehicular traffic to the freeway where there are no pedestrians.  Ditto for bicycle safety.
4. Removal of railroad grade crossings.  Prevents the conflicts between trains and vehicles.
5. Decrease in travel time.  A reduction in travel time is beneficial in many respects from road rage reduction to emission reduction.

[Duke87]

More complex than that, NE2. "Latent demand" also includes demand that can't be served during peak hours due to queuing. If your capacity is 6800 and you have 7500 vehicles trying to push through in an hour, you'll get 700 vehicles queued at the end of the hour (more, really, because breakdown flow has a lower capacity). Open up a new lane, suddenly instead of 6800 your volumes "magically" jump to 7500. Then you have vehicles on parallel routes getting around the 700-vehicle backup that see the new capacity open and think, "well as long as that's moving, it'll be faster." That can be another 1000 vehicles easily, and suddenly you've just eaten up everything you opened - without one new vehicle in the system.

So then build two or three new lanes instead of just one. Or build a new lane and a transit line. Or two transit lines.

Latent demand isn't a case against expansion. It just means you have to satisfy all the latent demand before your capacity improvement improves traffic flow.

As for HOT lanes, they do have their benefit to traffic - and they are new lanes added (if done right), so they are a capacity expansion. The real benefit, though, is that they generate revenue.