Relationship of Average Car Speed vs Speed limit

[Vic]

Originally posted by: mwmorph
You should have drive around he beltway during lighter traffic periods

Posted limit is 65 but 85-90 is normal in the left lane. Every once in a while there's that jerkoff in his 3 series doing 105 and weaving in and out of traffic like he was at Daytona but the norm seemed to be 85 in my experience.

And if the posted limit was 90, most people would still be doing about 85-90 with that occasional jerkoff doing 105.

 

[Chiropteran]

Originally posted by: pontifex

say the cop makes $30k a year. will he write enough tickets to cover that cost and brign in a profit? seems like hiring more cops would be the last thing they'd want to do to generate more income.

Read my post in context. The post I was responding to said government doesn't raise the speed limit because that would reduce income from speeding tickets. If what you are saying is true, then less speeders = less cops = less money spend on cops, cop cars, courts, etc.

I was saying that the limitation on ticketing speeders had nothing to do with the number of people who speed, but rather with the number of cops who are speed duty.

 

[LS21]

Originally posted by: Chiropteran

I was saying that the limitation on ticketing speeders had nothing to do with the number of people who speed, but rather with the number of cops who are speed duty.

your text said "they could just hire more cops"

 

[Chiropteran]

Originally posted by: LS21

Originally posted by: Chiropteran

I was saying that the limitation on ticketing speeders had nothing to do with the number of people who speed, but rather with the number of cops who are speed duty.

your text said "they could just hire more cops"

Yes it did, but I included quoted text from the post I was responding to that you should have read for context.

Originally posted by: Dark Jedi

I agree as well. I doubt the government is too keen on raising the speed limit. Speed tickets are a very nice source of income for them.

I took Dark Jedi's post to imply that raising speed limits would reduce the number of speeders such that cops would be running out of people to pull over.

That is why in my post I pointed out that currently cops are not even 1% of the way to running out of people to pull over. The real limitation on ticketing is the number of cops, not the number of speeders. You want more tickets, you hire more cops. You reduce the number of speeders and leave the number of cops alone, you can still get the same number of tickets because the number of ticketed speeders is such a tiny percentage of total speeders.

 

[ElFenix]

oddly enough, back when the speed limits were under state control in the 60s and 70s, most people went the limit. then when the feds got involved and dropped it nationwide to 55, people got used to speeding 5 over at least. so when the states got control of it again in the early 90s, everyone was so used to speeding that everyone sped up.

or so i heard.

 

[potato28]

People around here do 30-60 kph over the normal limit all the time, even on residential roads.

 

[Kadarin]

IIRC people tend to drive at a speed they are comfortable with, given road conditions and posted speed limit.

 

[mwmorph]

Originally posted by: Vic

Originally posted by: mwmorph
You should have drive around he beltway during lighter traffic periods

Posted limit is 65 but 85-90 is normal in the left lane. Every once in a while there's that jerkoff in his 3 series doing 105 and weaving in and out of traffic like he was at Daytona but the norm seemed to be 85 in my experience.

And if the posted limit was 90, most people would still be doing about 85-90 with that occasional jerkoff doing 105.

That's exactly what I tried to say in my first post. I mean people will pleatu at a certain speed and 85-90 seems like where everyone is comfortable at so why not set the speed limit at 80mph/130kph and leave it at that? I could list all the countries that adopted the 130kph law but it would be too long. I mean Italy, Germany and Greece haven;t gone to hell have they?

 

[hellokeith]

80 mph is about the nominal high speed on Dallas freeways (when there isn't traffic or an accident). People don't really pay attention to the signs. The Toll Tag booths say 45 mph but people still do >65 through them.

>70 feels fast in my car, but it's old and has a rigid suspension. I'd imagine all the suv's and extended cab extended bed duly raised turbo diesel trucks I see probably cruise very comfortably at 80-85.

So I don't think it'd matter that much. I guess if you posted 100 mph sign, it'd just cut down on the aforementioned beemer teens speeding tickets.

 

[onlyCOpunk]

Where I grew up the Speed limits everywhere are 75 and everyone always goes 80-85. I think eventually people's speed would max out at around 85-90 anyways. And lets face it whether youre going 75 or 90 if you crash you're going to die.

 

[irishScott]

Originally posted by: Chiropteran
So all of you yes-men, what do you think explains the lack of this holding true in the case of the local HOV lanes?

I also live in the Northern VA/DC area, and I know that if the speed limit is 65, I'll instinctively notice and cut if off at 20 over (assuming traffic is complying). When I was visiting my relatives in NC, where the speed limit was 75, I was going 95 without even noticing.

 

[BeauJangles]

For me, my speed depends a lot on the car I'm driving. Unconsciously, I'll accelerate until the car feels like it'll have to work very hard to add more speed. For my mom's VW that speed is 75. For my friend's porsche 911 turbo that speed is 110. For my old boss's e55 AMG, it's about 95.

I agree that most people won't exceed a certain speed, but I think the speed people choose to speed at it is also determined by what car they drive.

 

[JEDI]

Originally posted by: WingZero94
Yes

 

[alphatarget1]

It really depends on the drivers and the location, methinks. Traffic engineers are supposed to set speed limits around the 85th percentile of average speed.

BSCE graduate, I know a little about this stuff

 

[Gothgar]

yeah, but if they up the speed limit they'll lose a huge part of their revenue...

 

[91TTZ]

Originally posted by: Mermaidman
I believe *most* people drive at a speed that feels appropriate, a function of:
-condition of road/traffic/weather
-type/capability of car
-perceived driving aptitude

Agreed.

 

[91TTZ]

Originally posted by: shocksyde
People will always speed. If the limit is 90, they'll think, "well, I can probably get away with 95."

I do it all the time. Speed limit is 55. I drive 65, figuring I won't get pulled over. I've only been pulled over while going 50 in a 35 and 80 in a 55.

Yes, I know speeding is bad. Shut it.

There will be a certain point that you no longer feel safe going any faster. Don't make it sound like you have no self control and that you'd go out of control if the government was ruling you with an iron fist.

In my experience people will tend to average around 80 mph on an open highway regardless of what the posted speed limit is. If there was no speed limit, they'd still go the same speed. When I went to Germany and drove on the highways over there, people went about 80 mph even though there was no speed limit. The same holds true here.

 

[Throckmorton]

Originally posted by: Dark Jedi

Originally posted by: Mermaidman
I believe *most* people drive at a speed that feels appropriate, a function of:
-condition of road/traffic/weather
-type/capability of car
-perceived driving aptitude

I agree as well. I doubt the government is too keen on raising the speed limit. Speed tickets are a very nice source of income for them.

The government? What government?

 

[middlehead]

Do you think people would still drive 80mph, if the limit was raised to 75mph?

Interstate limit is 75 here, speeders go at least 80 if not 85.

 

[TallBill]

Originally posted by: jagec
No.

While I am not a traffic engineer, I did read a paper about how speed limits are set. On most roads, there is a "natural speed" that most drivers tend to use, which feels safe and comfortable. This is obviously lower on narrow, twisting roads, higher on flat, smooth, wide roads. In setting the speed limit, they basically pick the "85th percentile" speed, which is the speed which 85% of drivers do not exceed, chop 5-10MPH off of that, and post the sign. Later on when they build new roads, they can look to old ones with a similar layout when they set the speed limit.

Drive around a while and you will see that this is true. On most roads posted 60-70, traffic flows 0-10 over on average. This varies slightly by region. On open highways posted 35-55, people tend to speed a bit more, ~15 over isn't uncommon. In residential areas posted 25-40, people tend to drive the limit or somewhat under. The West Seattle Bridge here in Seattle is a closed-access raised bridge posted at 35-45, and yet people go 45-60 on it all the time, and then when they get onto I5 (60MPH limit) they only go 60-70.

So basically, if the speed limit were 100, most people would only be driving ~80. Of course there are always a few idiots. But if you want to make people slow down, just don't give them wide-open roads!

I was just going to post the 85th percentile. Also, this percent changes based off of weather conditions, time of day, etc. So a "good" speeding ticket is one that is for a person going over the current 85th percentile.

Afterall it isn't illegal to drive over the speed limit. It is illegal to drive at an unsafe speed, using the speed limit as a general guideline.

People have actually fought tickets because new survey data suggests that a speed limit should be raised.

Of course, this isn't always true for highways. Speed limit is 55 on the one I take to school and average speed is around 75-80 mph.

 

[3chordcharlie]

Originally posted by: pontifex

Originally posted by: Mermaidman
I believe *most* people drive at a speed that feels appropriate, a function of:
-condition of road/traffic/weather
-type/capability of car
-perceived driving aptitude

agreed.
i don't think people would drive even faster with a higher speed limit.

Ask yourself:

If my speedometer failed (and your tach, so no one decides to be 'clever'), and there were no traffic around you to inform your speed, would you all of a sudden be incapable of driving safely?

Of course not.

Speed limits are lower than the speed that your vehicle (whoever you might be) can navigate roads, because there are lesser vehicles, fuel efficiency and political considerations, but take away the speed limit, and you wouldn't just drive with your foot to the floor until you inevitably crashed.

 

[thomsbrain]

I did some research on this for a project once.

When Michigan raised their speed limits from 55 MPH to 65 MPH, average speeds increased by only 1 percent.

Here's a direct quote from a Department of Transportation study: "Raising speed limits by 5, 10, 15, or 20 mph? had a minor effect on vehicle speeds."

For the most part, people drive the speed at which they feel comfortable driving, regardless of the limit.

There is tons of data out there to support the theory that higher speed limits and higher overall speeds both support reductions in speed variance and accident rates. Support comes from reports from NHTSA, DOT, AAA, Institute of Transportation Engineers, etc.

The DOT are the first to admit that most highway agencies set speed limits below the average speed of the traffic and that speed limits are set artificially lower than their own recommended "85th percentile" speed.

 

[thomsbrain]

Originally posted by: ElFenix
oddly enough, back when the speed limits were under state control in the 60s and 70s, most people went the limit. then when the feds got involved and dropped it nationwide to 55, people got used to speeding 5 over at least. so when the states got control of it again in the early 90s, everyone was so used to speeding that everyone sped up.

or so i heard.

That is not what actually happened according to the data.

 

[Baked]

I get on the freeway, change to the 2nd lane to the left, and set cruise to 65. If there are no traffic around, I set it to 70. On the local, I go 5 above post.

 

[legoman666]

I'll go 65 in a 55, 60 in a 50, and 72-75 in a 65. Rarely do I ever go over 75.