Pay a toll, drive faster

[Alex]

I think having a higher speed limit on a toll road is a good idea, like a perk for paying to drive the road (as long as its standards can accommodate it, like the 85 mph in TX). It is the toll roads with 55 mph speed limits that should be 65 or 70 that makes me question, "what am I paying for?"

[kphoger]

I think having a higher speed limit on a toll road is a good idea, like a perk for paying to drive the road (as long as its standards can accommodate it, like the 85 mph in TX). It is the toll roads with 55 mph speed limits that should be 65 or 70 that makes me question, "what am I paying for?"

Speaking of the 85-mph highway in Texas....  The toll road agency had it as part of its contract with the state of Texas that it would pay the state $67 million if the road got an 80-mph limit, whereas it would pay the state $100 million if the road got an 85-mph limit.  What do you think about that?

[roadman65]

Money talks.

[InterstateNG]

I think having a higher speed limit on a toll road is a good idea, like a perk for paying to drive the road (as long as its standards can accommodate it, like the 85 mph in TX). It is the toll roads with 55 mph speed limits that should be 65 or 70 that makes me question, "what am I paying for?"

Speaking of the 85-mph highway in Texas....  The toll road agency had it as part of its contract with the state of Texas that it would pay the state $67 million if the road got an 80-mph limit, whereas it would pay the state $100 million if the road got an 85-mph limit.  What do you think about that?

A speed limit of 85 is going to be perfectly acceptable when that road (130) is complete.  Traffic is going to be very sparse.

That's not fishy at all, but what is fishy is the signing of the frontage roads (US 183) as 55mph between Mustang Ridge and Lockhart.

[Crazy Volvo Guy]

The Indian Nation is worse than the Will Rogers and Turner. Its design standards are abysmal; I'd estimate the median at 4 feet, and most of the bridges are divided with only a raised curb.

It's like they said "Hey! Let's copy the original Pennsylvania Turnpike design!"

[J N Winkler]

Speaking of the 85-mph highway in Texas....  The toll road agency had it as part of its contract with the state of Texas that it would pay the state $67 million if the road got an 80-mph limit, whereas it would pay the state $100 million if the road got an 85-mph limit.  What do you think about that?

In the dictionary, this is used to illustrate the term perverse incentive.

[oscar]

Speaking of the 85-mph highway in Texas....  The toll road agency had it as part of its contract with the state of Texas that it would pay the state $67 million if the road got an 80-mph limit, whereas it would pay the state $100 million if the road got an 85-mph limit.  What do you think about that?

In the dictionary, this is used to illustrate the term perverse incentive.

"Perverse"?!  Only if one thinks the highway wasn't designed for safe travel at an 85mph limit.  If it was, the incentive only encourages the state to do what it should be doing anyway.

[J N Winkler]

"Perverse"?!  Only if one thinks the highway wasn't designed for safe travel at an 85mph limit.  If it was, the incentive only encourages the state to do what it should be doing anyway.

Yup:  perverse.  The title-sheet design speed for all of the segments of SH 130 for which I have obtained construction plans is 70 MPH.  Now, I will grant you that there is probably enough slack in the design to support safe speed limits of 85 MPH or even higher.  But the perversity of the incentive arises from the fact that the added money encourages TxDOT to find that 85 MPH speed limits are safe, regardless of whether they are or not, and indeed, regardless of whether TxDOT responds to that encouragement by allowing its speed limit determination to be influenced in any way by the added cash.

This perverse incentive can be removed in at least two ways:  (1) TxDOT's payouts from its CDA partner not being related to the speed limit in any way, or (2) TxDOT and the CDA partner agreeing that the speed limit will be the title-sheet design speed, which obliges the latter actually to use an 85 MPH design speed if it wants an 85 MPH speed limit.

[Revive 755]

Um, there isn't a speed limit in this country that doesn't have some sort of political influence.  Find me 1 state that doesn't have a law regarding a maximum speed limit.

Maybe I'm reading it wrong, but it seems in Minnesota the DOT can go above the otherwise normal limits if warranted.  See Subdivision 4 of https://www.revisor.mn.gov/bin/getpub.php?type=s&year=current&num=169.14

[oscar]

Um, there isn't a speed limit in this country that doesn't have some sort of political influence.  Find me 1 state that doesn't have a law regarding a maximum speed limit.

Maybe I'm reading it wrong, but it seems in Minnesota the DOT can go above the otherwise normal limits if warranted.  See Subdivision 4 of https://www.revisor.mn.gov/bin/getpub.php?type=s&year=current&num=169.14

Even if the law nominally gives a DOT broad discretion to set speed limits, that doesn't cut the politicos out of the action entirely.  For example, AFAIK, Hawaii for a long time had no statutory maximum speed limit, and even now the only statutory limit is one defining reckless driving as 80mph or higher.  Still, Hawaii DOT moved very gingerly (after consulation with politicians, in the aftermath of a spectacularly failed experiment in photo radar speed enforcement) to raise some freeway speed limits from 55mph to 60mph, and hasn't yet dared to return any of them to the pre-NMSL maximum of 65mph. 

[bjrush]

It may look perverse but in my experience engineers are very ethical people...not to mention it's their ass if they sign off on a higher speed limit

[cpzilliacus]

Just because a road is tolled does not mean the speed limit should be higher. Speed limits should be based only on what is safe, and on engineering principles. Political meddling with them is stupid.

I agree. 

When it comes to speed and toll roads, I am personally much more interested in the variability of the actual observed speeds, not the maximum legal speed limit.   

Toll roads need to "sell" that they can get a driver from point A to point B reliably in a predictable amount of time, which (in some cases) means that 50 MPH or 55 MPH is perfectly acceptable.

[J N Winkler]

It may look perverse but in my experience engineers are very ethical people...not to mention it's their ass if they sign off on a higher speed limit

In my experience too, engineers strive to adhere to high ethical standards.  But they have to eat just like the rest of us.  Also, fixing a speed limit is not something that can be done easily to hard-and-fast objective criteria, like determining the acceptable load for a bridge:  no clear physical relationships are involved and the research findings are notoriously cloudy.  This means that setting a speed limit involves substantial exercise of discretion ("engineering judgment") and that in turn implies that an engineer is less likely to be held liable for bad engineering practice if he sets a speed limit too high than if a bridge collapses.

In short, for an engineer assigned the problem of deciding whether a given toll road is safe for an 85 MPH limit, the cash incentive means that the downside risks are greater for a negative determination than for a positive one.  In practice, however, responsibility for speed limit determinations is not assigned in a vacuum, and I suspect the decision as to the safety or otherwise of an 85 MPH limit would be delegated to an engineer whose bosses' past experience suggests will be more likely to support higher speed limits anyway.

[vdeane]

It may look perverse but in my experience engineers are very ethical people...not to mention it's their ass if they sign off on a higher speed limit

Raising speed limits is unethical?  I would think the opposite would be true.  For a lower limit you inconvenienced thousands of drivers.  If a limit is too high (something that is very rare indeed) and someone gets into an accident, it's their own fault for driving faster than conditions warranted just because of some number on a sign.  If you can't realize you're driving too fast for conditions without a sign telling you, you shouldn't be driving.

[bjrush]

I meant raising speed limits above a safe and acceptable limit. Doing such a thing would be unethical and I bet most engineers agree. If the increases are within safety specs, what I was saying doesn't apply.

[Scott5114]

I meant raising speed limits above a safe and acceptable limit. Doing such a thing would be unethical and I bet most engineers agree.

I doubt German engineers would.

[codyg1985]

It may look perverse but in my experience engineers are very ethical people...not to mention it's their ass if they sign off on a higher speed limit

This is very true. Engineers are scared of lawsuits like crazy these days. Most P.E. carry a $1 million insurance policy against such lawsuits. Even if you did everything right, you may still get caught up in paying a lot of legal fees if a lawsuit ever came up.

Design speed is a factor that goes into quite a bit of highway design. As long as the highway was built to that design speed, then it shouldn't be an issue.

Then again, it may not be that the engineer signed off on a higher speed limit but more that the politicians went above and beyond the original design intent.

[Revive 755]

Raising speed limits is unethical?  I would think the opposite would be true.  For a lower limit you inconvenienced thousands of drivers.  If a limit is too high (something that is very rare indeed) and someone gets into an accident, it's their own fault for driving faster than conditions warranted just because of some number on a sign.  If you can't realize you're driving too fast for conditions without a sign telling you, you shouldn't be driving.

I don't think the 'driving faster than conditions warranted' holds up in court.

The best way to handle the motorist inconvenience vs. safety is to probably post a somewhat reasonable speed limit, but overdue the advisory signage with lots of advisory speed plaques.

Nonetheless, engineering is often a no-win occupation.

[Duke87]

I meant raising speed limits above a safe and acceptable limit. Doing such a thing would be unethical and I bet most engineers agree. If the increases are within safety specs, what I was saying doesn't apply.

Indeed, but reality isn't so simple. While usually the intent when designing a road is that it will be posted 5 or 10 MPH below its design speed, many aspects of the design speed in the first place make some conservative assumptions about things such as drivers' reaction time - 2.2 seconds, if I recall correctly from my highway design class. Which is a lot. While you are not going to find someone who takes longer than that to react (which is the idea), most people will take less, especially if they're alert. For reasons such as this, in reality, "safe speed" depends on more than just the geometry of the road, the weather conditions, and the amount of traffic - it also depends on what vehicle is being driven, by whom, and in what mental state.

Most drivers are well aware of what their capabilities are and do not need a sign with a number on it to tell them how fast they should drive. Speed limits as we know them are for regulatory purposes only and exist only for the sake of having something which can be enforced. And since they are regulatory, they inevitably (unfortunately) end up subject to political rather than practical judgment. Yesterday as I was leaving my cousin's house, I was driving on a road where the speed limit was 30 and I was doing 30 since it was a narrow twisty road and much more wouldn't be practical. But then I turned off onto a wider, straighter, more major road, and while I started doing 40, the speed limit was still 30. Simply because 30 is the maximum that town allows for local streets, regardless of practical consideration.

If a limit is too high (something that is very rare indeed) and someone gets into an accident, it's their own fault for driving faster than conditions warranted just because of some number on a sign.  If you can't realize you're driving too fast for conditions without a sign telling you, you shouldn't be driving.

I don't think the 'driving faster than conditions warranted' holds up in court.

If you cause an accident you are legally "at fault" regardless of how fast you were going, so the speed limit doesn't matter there. As for a higher limit requiring a higher speed to get ticketed, well yeah, that's the idea. Get the cops to leave ordinary drivers alone and only let them pull the real scofflaws over.

[jeffandnicole]

Um, there isn't a speed limit in this country that doesn't have some sort of political influence.  Find me 1 state that doesn't have a law regarding a maximum speed limit.

Maybe I'm reading it wrong, but it seems in Minnesota the DOT can go above the otherwise normal limits if warranted.  See Subdivision 4 of https://www.revisor.mn.gov/bin/getpub.php?type=s&year=current&num=169.14

Even if the law nominally gives a DOT broad discretion to set speed limits, that doesn't cut the politicos out of the action entirely.  For example, AFAIK, Hawaii for a long time had no statutory maximum speed limit, and even now the only statutory limit is one defining reckless driving as 80mph or higher.  Still, Hawaii DOT moved very gingerly (after consulation with politicians, in the aftermath of a spectacularly failed experiment in photo radar speed enforcement) to raise some freeway speed limits from 55mph to 60mph, and hasn't yet dared to return any of them to the pre-NMSL maximum of 65mph. 

NJ doesn't have one either, although it's often mis-interperted.

Per NJ law, the speed limit, unless otherwise signed, is 25 in any business and residential districts, 35 mph in suburban business and residental district (yes, the 25 mph says "any", so the 35 mph subsection doesn't make any sense), and 50 mph in all other locations.

In many online charts, 50 mph is listed to be the maximum limit on non-interstate highways, which is false also.

During the NMSL, 55 was never listed as a maximum speed limit anywhere on the NJ law books.  Which made the fight to change the law to 65 mph absurd, because there was no law stating what the max speed limit was.  Even now, the law states "Fifty miles per hour in all other locations, except as otherwise provided in the "Sixty-Five MPH Speed Limit Implementation Act...". But the law still never states the maximum speed limit is 65 mph!

[Alps]

Per NJ law, the speed limit, unless otherwise signed, is 25 in any business and residential districts, 35 mph in suburban business and residental district (yes, the 25 mph says "any", so the 35 mph subsection doesn't make any sense), and 50 mph in all other locations.

The 25-35-50 was my initial impression of the law, and after years of seeing nothing to corroborate it, I gave up on the 35 part. Finally, someone else saw what I saw!

[mjb2002]

In South Carolina, the speed limit is 70 mph for all roads - toll and free. Of course, Interstate 185 in Greenville County is the only toll road that I know of in the state (to date).

[NE2]

In South Carolina, the speed limit is 70 mph for all roads - toll and free.

All roads? Damn.

Of course, Interstate 185 in Greenville County is the only toll road that I know of in the state (to date).

US 278 on Hilton Head Island.

[Alps]

In South Carolina, the speed limit is 70 mph for all roads - toll and free.

All roads? Damn.

That'll make my upcoming trip that much shorter!

[wxfree]

I really think that speed limits should reflect safety and efficiency, and not toll (or speeding ticket) revenue, so I don't think we should have higher limits for pay roads.  Toll roads may be better suited for higher speeds if they have better design and lighter traffic, but high-class free roads with equivalent design and light traffic should qualify for the same speed limits.

On the other hand, sometimes they want you to pay a toll to drive slower.  On the Chisholm Trail Parkway project in Fort Worth, the proposed speed limit on the north end, between I-30 and I-20, is 50 mph.  The artificially low speed limit is intended to reduce noise impact in the surrounding residential area.  There's also discussion of charging a higher rate, I've heard 4 cents per mile extra, to pay for the extra aesthetics.  I haven't seen that in any of the documents, but it's been said at public meetings.  This portion of road is surrounded on all 4 sides by freeways, so it's the least competitive section, and they want to charge people an extra-high toll to drive slower than all of the surrounding freeways.

This ridiculous speed limit not only disincentivizes toll-paying, but is unsafe.  Rule followers, and people with warrants, will go 50, while people wanting to drive a reasonable speed (and get some value for their toll money) will probably be going 70-75.