July 12, 2006
Full speed ahead!

Would you pay a toll if you could drive faster? Via Toll Road News, you may get that opportunity, in Austin and perhaps soon elsewhere.

Posted speed limits are a major financial issue in the terms of the toll concession for Texas State Highway 130 Segments 5 and 6 (TX130-S for South). The fine print of the concession agreement now available on the TxDOT website shows that posted speed limits are seen as a key to attracting large volumes of traffic from free-competitor I-35.

Exhibit 7 (Ex7) titled Compensation Terms provides that the concessionaire will pay TxDOT three radically different amounts of money depending on the legally enacted speed limits for the new tollroad (TR).


Exhibit 7 provides for two approaches for the state to garner a share of higher speed toll revenues: (1) higher upfront concession fees or (2) a higher share of annual toll revenues.

$25m for 75mph, $92m for 80mph, $125m for 85mph

Most rural expressways in Texas were posted for speeds up to 70mph when the concession was negotiated but in the past month have been increased to 75mph (121km/hr). So without special treatment TX130 would now be posted 75mph. At that posted speed TxDOT only gets $25m upfront fee. Ex7.A.2 reads: "In the event TxDOT authorizes, within 180 days after the Service Commencement Date, a maximum daytime posted speed limit for passenger vehicles of 80 miles per hour on the Facility, other than in populated areas or other specific locations where design does not accommodate such speed, and TxDOT affirmatively elects in writing to waive increased revenue sharing under Part B respecting such posted speed limit, Developer shall pay to TxDOT an additional $67 million." There is more refinement on the timing.

Then in Ex7.A.3 the agreement reads that if TxDOT authorizes 85mph for passenger vehicles the concessionaire must pay an extra $100m in upfront fee.

80mph is now the legal posted maximum speed on a 695km (432mi) stretch of I-10 and on 143km (89mi) of I-20 in the west of Texas so there is precedent for 80mph, but there are no highways yet with 85mph posted. In a peculiarity of the law on speed limits in Texas higher speeds are not flat illegal but "prime facie" (considered on their face) to be unsafe speeds and an offense.

Basically, in order to lure more drivers to this toll road, which skirts around Austin, the private owner Cintra (the same outfit that's been bidding on the Trans Texas Corridor) will pay more up front for the right to set a speed limit of 85 MPH.

Jose Maria Lopez de Fuentes, head of Cintra in North America told us in an interview: "This will be a very safe road built to the most modern standards and we think it can operate safely at higher speeds. At higher speeds our studies show we get significantly more traffic, but the decision is up to Texas legislators. We have structured the concession so if we attract more traffic from higher speed, we share the revenues with the state - either in a larger upfront payment or in larger year by year revenue sharing."

COMMENT: There is a lot of inherent logic to this approach. If the 130 TR is to act as an toll express lanes alternative to free I-35 then speeds will play a major role in determining how much traffic the toll road attracts. However the road safety lobby are liable to go ballistic over this approach (they probably haven't discovered it yet). The safety lobby think there is some inherently 'safe' speed for different classes of roads and - we guess - will demagogue the issue of higher speeds being encouraged to earn more toll revenues and more money for TxDOT. We have to wonder whether TxDOT and the concessionaire have spokesmen capable of articulating the case for high speeds.


Is there going to be the political will to enforce lower speeds on I-35 sufficiently to give the 130 TR the advantage intended by any legislation? And if such legislation were passed would it be sustained in the face of protests against a law designed to benefit the TR. Would it sustain a random run of newsworthy crashes on 130? Seems doubtful to us.

Note how the question of whether or not it's actually safe to allow such high speeds is not considered. I'm surprised they didn't consider the possibility of a wrongful death suit claiming that to allow such speeds is reckless and negligent. One also wonders whether enforcing a lower speed on I-35 might eventually mean reducing the current speed limit if the initial usage of the new toll road falls short of projections.

But what are the traffic and revenue prospects? Given that most traffic is local and this pike won't get much local traffic the numbers are bound to be light.

The executive summary of the state's assessment of TX130 - the whole 89mi (143km) project segments 1 thru 6 - said on traffic: "Year 2020 forecasts of SH 130 traffic range from a high of 124,000 vpd within the northern, more urbanized portion of the corridor, to a low of 22,000 vpd in the southern, more rural area." Lopez told us the studies they have had commissioned suggest higher traffic than the state's older estimate. Higher than 22k apparently.

Say 25k to 30k? At 27k and assuming an average trip length of 30mi and an average toll of 20c/mi you have annual toll revenue in 2020 of $59m. They are spending about $1325m ($1300m project cost plus concession fee $25m), or 22 times gross revenue. That's below the ratios of 30 to 40 paid for the Chicago Skyway, Indiana TR and Pocahontas Parkway, and clearly there is no early profit to be had in any of these. The prices being paid are based on projections of much larger returns decades off. Whether they are discounting adequately for risk and to present value is a matter for argument. (Our gut feeling on TX130-S is they aren't discounting adequately and that traffic may well be very light, only 10k or so, for some years, but it would be nice to see some traffic and revenue studies and the assumptions they make.)

A real speed differential in favor of the TR would help a lot, but we wonder how much actual speeds are affected by posted speeds.

Well, as we know, the real speed limit on any road is 10 MPH above what's posted, so I guess the prospect of pushing 100 might be a draw for some. It might also be a deterrent. Lord knows I'd be pretty skittish about it, and I don't consider myself a slowpoke by any stretch.

Another thing to consider, especially in these times of high gas prices, is the effect of all this extra speed on one's mileage.

For most cars, the "sweet spot" on the speedometer is in the range of 40-60 mph. Cars with a higher road load will reach the sweet spot at a lower speed. Some of the main factors that determine the road load of the car are:

  • Coefficient of drag. This is an indicator of how aerodynamic a car is due only to its shape. The most aerodynamic cars today have a drag coefficient that is about half that of some pickups and SUVs.

  • Frontal area. This depends mostly on the size of the car. Big SUVs have more than double the frontal area of some small cars.

  • Weight. This affects the amount of drag the tires put on the car. Big SUVs can weigh two to three times what the smallest cars weigh.

In general, smaller, lighter, more aerodynamic cars will get their best mileage at higher speeds. Bigger, heavier, less aerodynamic vehicles will get their best mileage at lower speeds.

Imagine what doing 85 MPH does to a semi's mileage. Since big rigs are a targeted audience for this road, has anyone considered the possibility that there's diminishing returns in a higher speed limit? I'm just asking.

Getting back to the safety issue for a minute, I'd have to say that the "road safety lobby" needs to hone its response a bit.

As for the safety questions raised by that higher speed, [Phil Russell, director of the Texas Department of Transportation's turnpike division] said the agency is working on design standards for the Trans-Texas Corridor, a proposed 4,000-mile network of toll roads, that would make them as safe at 85 mph as interstates are at 70 mph.

"Whatever the speed limit is, we're going to make sure our design standards can accommodate it," Russell said Monday.

Judie Stone, president of the Washington-based Advocates for Highway and Auto Safety, doesn't buy it.

"I just think it's a violation of public health responsibilities on the part of the state," Stone said. "It's the first time I've ever heard of anything like that. Following on the heels of raising the speed limit to 80 on some segments of the interstates, it's very disturbing. It sounds like safety's for sale in Texas."

Some numbers might be helpful here. Sal Costello, from whom I got these links, quotes a press release that says "Nearly 40 percent of the 3,600 people killed on Texas roads in 2004 were speed-related crashes". That's great to know, but what if you want to impress people, how about telling them how much more likely they are to die in a crash at 85 than they are in one at 55 or 65? Telling me would be nice, too, since my Google muse seems to have abandoned me on this one.

So. Would you pay to be able to drive faster? If so, how fast is too fast? Leave a comment and let me know.

Posted by Charles Kuffner on July 12, 2006 to Planes, Trains, and Automobiles | TrackBack

The most efficient speed on any vehicle is that speed at which the vehichle operates using the highest gear at the lowest RPM.

Posted by: Patrick on July 12, 2006 7:54 AM

Normally I agree with the belief that if you raise a speed limit to the speed most people are driving, they will just increase their speed again (so they'd again be speeding).

But I think that has limits.

Above about 75 or 80, regardless of the posted speed limit, I begin to feel uncomfortable, and I don't think I'm alone. In other words, just because I might do 75 in a 70 zone doesn't mean I'd do 85 on the 80 MPH stretch of I-10 in west Texas.

My primary concern with the higher speeds is one of speed differential. No doubt you will have people willing to pay to avoid the congestion of I-35 even if they don't want to drive (say) 80 or 85. They may be comfortable with, say, 60-65. But that would create a large speed differential, which I think is more dangerous than the speed itself. If everyone wanted to do 80 or 85, it would be less dangerous than if one-third of the drivers were doing 70 or less.

Having said all that, I'd probably reserve final judgment until I was familiar with the final design and the amount of traffic. I'd probably err on the side of keeping speed limits down a bit and doing traffic studies to see where the 85th percentile speed was, and only then increasing the limit if the study warranted it.

Posted by: Tim on July 12, 2006 9:24 AM

I'm fairly certain that these speeds would not apply to trucks. The 80 mph limit is West Texas is for cars and light trucks only.

I want to suspect that the proposed 85 mph limit was floated just so that the "compromise at 80 mph" will seem reasonable. Still, that is a significant fee increase for the higher speed.

Posted by: Jeb on July 12, 2006 10:54 AM

Jeb - If you're right, then that really is dangerous to have cars going at 80 or more and trucks limited to 65 or 70. Tim is right on about speed differential.

And I suspect you may be right about the 80 MPH "compromise". We'll see.

Posted by: Charles Kuffner on July 12, 2006 10:59 AM

Just drive on any freeway anywhere in the US , look at your speedometer .

On a controlled access highway In free flowing traffic 70 to 85 mph is normal traffic flow speed .

We are all driving at these speeds every time we get on the highway and the death rate has dropped to the lowest rate per million miles traveled in the history of driving and keeping records .

Post the limit at 85 mph or do away with all limits , it will make no difference in the speed we are driving .

Montana had a lower death rate when they had no daytime limit . I drove 90 mph for over 10 hours while crossing the state when no daytime limit was the law and didn't die . 85 mph limit doesn't scare me any bit .

Texas should adopt Reasonable & Prudent law then follow suit with a posted suggested limit of 75 or 80 mph . All the roads would be safer .

Posted by: acorn on July 18, 2006 5:26 PM

My best that evidence speed limits are too low in USA, is the AASHTO Green Book. The term design speed, by definition is quite interesting. If the design speed is 65mph, it means the roads sharpest curve, accommodates safe travel at 65mph for the worst of case vehicle. If you run a compact car instead of an SUV or 18-wheeler, then you are double safe. Furthermore: if the road is straight, then you are tripple safe. Finally, the policy in US is such, that the posted speed limit never exceeds the design speed. The government really wraps up the driver into protective cushioning!

Posted by: Andre on November 25, 2006 2:05 PM