Utah Lawmaker seeks to increase some interstate speeds

[accadacca]

I'm all for it. It's awesome driving south on I-15. I can get to the bottom if the state in under 4 hours.

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SALT LAKE CITY

[double moo]

succumbing to the big oil lobby?

[jman]

Increased speeds will be nice, however, you literally have to be phone free, music free, and conversation free in order to make people go 65. My mother is that way. If you have any conversation with her, she immediately drops down to 55 on the freeway and keeps looking at you when you speak.

Alright, time for a tangent as Utah roads drive me crazy!! Utah civil engineers need to up there game, desperately! Sure we have huge streets, but it's very inefficient!

Little to no emphasis or incentives to take mass transit, roundabouts that suck, on-ramps/off-ramps that converge way too late (thereby encouraging people to "take there time" and barely hit 60mph at the freeway). Few banked turns - always, always flat as can be. No light reflectors at traffic stops to help people stay in there lane when turning. (see Layton City for prime example)

Ugh...Utah road engineers....I can go on and on.... Those things need to be taken care of before raising the speed limit.

[Sandstone Addiction]

Little to no emphasis or incentives to take mass transit, roundabouts that suck, on-ramps/off-ramps that converge way too late (thereby encouraging people to "take there time" and barely hit 60mph at the freeway). Few banked turns - always, always flat as can be. No light reflectors at traffic stops to help people stay in there lane when turning. (see Layton City for prime example)

Ugh...Utah road engineers....I can go on and on.... Those things need to be taken care of before raising the speed limit.

I agree that the roads in Layton are heinous. Takes forever to get anywhere. I-15 in Davis and Weber Co is long overdue for a major overhaul.

But, on the other hand, I 15 in Utah County is excellent and in SL County almost as good. I think the newer high flow intersections are genius. Although the one's like on Bangerter take some getting used to, for sure.

It seems like this proposed change is just to legitimize what most are doing already. Makes sense to me.

Overall, I think UDOT has made great strides over the decades and seem to be headed in the right direction.

[caverdan]

..

[cchoc]

As long as you don't understand kinetic energy it's perfectly reasonable. Kinetic energy is proportional to the mass times the square of velocity. It takes 2.25 times as much force to stop a vehicle going 75mph than it does the same vehicle going 50mph, 4 times as much at 100mph. The kinetic energy you have at whatever speed has to be reduced to zero by something in order for you to stop, hopefully your brakes.

[Scott P]

As long as you don't understand kinetic energy it's perfectly reasonable.

Yes, but it's also reasonable even if you do understand kinetic energy. Your calculations on kinetic energy are correct, but it is true that DOTs raise or drop speed limits based on speed studies. They can raise it as long as the posted speed doesn't exceed the design speed. If the road was designed for 70 mph and was posted at 55 mph, it can be raised to 65 mph after doing a speed study.

(As a side not, speed studies aren't based on an average speed of all vehicles, but by the percentage of vehicles going at a certain speed. Therefore someone can't drive through the speed study multiple times at 120mph and try to throw off the average, so don't bother trying it).

If a certain percentage of vehicles is driving at a speed higher than the posted speed limit (without any unusual accident histories on that section of road), but still lower than the design speed, it can be safer to raise the speed limit, kinetic energy and all.

Sometimes lower speed limits are requested by the city that the highway is going through. Sometimes some towns even intentionally want a road designed for a lower speed through town (by narrowing it, putting in curbs, etc.) just to slow people down. Sometimes, regardless of what the design speed says on paper, other factors can warrant dropping speed limits. Usually there will be accident histories to back it up. Places that get unusual wind, animal crossings, drunk people, whatever. It can be for a variety of reasons. Having a business with a lot of truck traffic, for example, that either opens or closes can affect accident rates.

(PS, the down side of raising speed limits beyond 55 mph is gas mileage. 30-55 mph is optimum gas mileage for most vehicles. It is difficult to design a car that has an optimum higher than 55 mph because of aerodynamic drag).

[Sandstone Addiction]

As long as you don't understand kinetic energy it's perfectly reasonable. Kinetic energy is proportional to the mass times the square of velocity. It takes 2.25 times as much force to stop a vehicle going 75mph than it does the same vehicle going 50mph, 4 times as much at 100mph. The kinetic energy you have at whatever speed has to be reduced to zero by something in order for you to stop, hopefully your brakes.

Our roads are relatively straight and flat around here, unlike "the land of grits and gravy".

BTW @cchoc --everytime I see your "Location" I start craving a hot bowl of grits with cheddar and bacon on top.

[cchoc]

Our roads are relatively straight and flat around here, unlike "the land of grits and gravy".

BTW @cchoc --everytime I see your "Location" I start craving a hot bowl of grits with cheddar and bacon on top.

I grew up in Kansas and spend a lot of time in Utah, so I do appreciate the straight roads. One more than one occasion I've had a LEO pass me on I40 going at least 100mph w/o lights or siren as I cruised along at 65, so I'm guessing they aren't physics majors. It's the difference in speed between the fastest and slowest that adds a lot of the danger to higher speed limits.

They used to serve a fine biscuits and gravy breakfast at Escalante Outfitters but they quit because most people just wanted to grab a muffin and head out in the morning. It made me very sad.

[BruteForce]

As long as you don't understand kinetic energy it's perfectly reasonable. Kinetic energy is proportional to the mass times the square of velocity. It takes 2.25 times as much force to stop a vehicle going 75mph than it does the same vehicle going 50mph, 4 times as much at 100mph. The kinetic energy you have at whatever speed has to be reduced to zero by something in order for you to stop, hopefully your brakes.

I figure my 10k truck hitting something at 55 -v- 75 will result in the same consequences.. Me turned into mush and anything I hit turned into mush..

[Swimswithtrout]

There's a speed limit in UT ? I don't even drive the Interstates. Unless you're driving 75-80 on a posted 65 mph US highway/State highway, you're going to be impeding traffic and have a long line of PO'd drivers behind you.