Relationship of Average Car Speed vs Speed limit

[Chiropteran]

I have seen evidence to the contrary.

Where I live, the northern VA/DC area, the main N/S interstate through DC (i395) has a central dedicated HOV lane. Certain times of the day, the HOV lane is open to all traffic- that is you don't need to actually be driving with a passenger to use it, so use is purely based on personal preference. I generally take the HOV lane when I can, because of the higher speed limit and fewer exits.

The normal interstate speed limit is 55, in the HOV lanes it is 65.

Yet, I have found that on both the HOV lanes and the normal lanes, the absolute hard limit for the vast majority of drivers is around 80mph. Almost every morning going in to work, the fastest non-HOV lane is moving at close to 80mph, 25mph above the legal limit. Almost every evening coming home from work, in the HOV lane, the fastest cars move about 80mph- about 15mph over the limit.

Here is a case where in one situation the speed limit is a full 10 mph higher than in the other, but in both cases the drivers choose to drive the same speed. You might think that speeders in the HOV lane would be driving close to 90mph, but I don't see that. Occasionally there are the idiots driving way faster than anyone else who are probably approaching 100mph, but I see them just as often in the regular lanes as the HOV lanes.

Is it similar in other areas? Do you think people would still drive 80mph, if the limit was raised to 75mph?


cliffs: HOV lane speed limit 65, regular lane limit 55. Speeders in either case typically drive around 80mph. Raising the speed limit doesn't seem to increase the speed that speeders drive at.

 

[WingZero94]

Yes

 

[SpunkyJones]

Originally posted by: WingZero94
Yes

 

[Capt Caveman]

Originally posted by: SpunkyJones

Originally posted by: WingZero94
Yes

 

[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?

 

[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

 

[Aikouka]

I think this is highly dependent on the road. I believe you're talking about the beltway (only lived in the NOVA/DC area for a couple months) and frankly, it's so jampacked there half the time that everyone ends up going the same speed (hence the 80mph). I believe if you had an example of a HOV lane on a less busy highway (which probably wouldn't get one since it's not so busy ), that you'd see people going faster in it.

Would I go faster? Probably, because my max is relative to the speed limit. I go SL+5 (to accomodate for people that like to speed yet still not being excessive) and if they raised a road from 55 to 65, I'd go 70 instead of 60. Of course, this example isn't too good since the new speed is above my old rate. If I went 10 over, I'd probably still go 10 over in the new area as well.

 

[Lonyo]

I'd say they'd go to 85~90 max in a 75 limit.

 

[Anubis]

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 with this, the majority of people also seem to drive ~8-12 MPH over the posted limit

if its 65 most drive ~75

its its 70 most drive 80

the exception to that is in and around cities where the limit can be 55 and everyone drives 90

 

[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!

 

[Illusio]

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.

 

[mwmorph]

Up to a point, at some speed, people will be no longer comfortable going any faster. I've done very short stretches at 120+mph when I was stupid and younger. Would I do 120 if the speed limit was 110? Hell no.

I'd say over 85 to 90mph is where 90-95% of drivers will no longer speed further. It's just tiring paying attention and driving well at 95mph for long stretches of freeway. I'd say if you set speed limits of 80mph, you'd be fine with the vast majority of people doing no more than 10 over.

After all, 80mph is just 130km/h which is standard on larger freeways in many foreign countries.

 

[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.

 

[ryan256]

Originally posted by: Capt Caveman

Originally posted by: SpunkyJones

Originally posted by: WingZero94
Yes

 

[Anubis]

Originally posted by: mwmorph
Up to a point, at some speed, people will be no longer comfortable going any faster. I've done very short stretches at 120+mph when I was stupid and younger. Would I do 120 if the speed limit was 110? Hell no.

I'd say over 85 to 90mph is where 90-95% of drivers will no longer speed further. It's just tiring paying attention and driving well at 95mph for long stretches of freeway. I'd say if you set speed limits of 80mph, you'd be fine with the vast majority of people doing no more than 10 over.

After all, 80mph is just 130km/h which is standard on larger freeways in many foreign countries.

after driving in places where the posted highway speed is 70-75 and driving 80-90
coming back to a posted speed of 65 makes you feel like you are going in slomo

 

[mwmorph]

Originally posted by: Anubis

Originally posted by: mwmorph
Up to a point, at some speed, people will be no longer comfortable going any faster. I've done very short stretches at 120+mph when I was stupid and younger. Would I do 120 if the speed limit was 110? Hell no.

I'd say over 85 to 90mph is where 90-95% of drivers will no longer speed further. It's just tiring paying attention and driving well at 95mph for long stretches of freeway. I'd say if you set speed limits of 80mph, you'd be fine with the vast majority of people doing no more than 10 over.

After all, 80mph is just 130km/h which is standard on larger freeways in many foreign countries.

after driving in places where the posted highway speed is 70-75 and driving 80-90
coming back to a posted speed of 65 makes you feel like you are going in slomo

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.

 

[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.

 

[BoomerD]

When the speed limits were 55 mph, people drove between 65 and 70. Now that they've been raised to 65, people drive between 75 and 80. (MOST people, not all...some obey the posted limits, others grossly exceed them)

To a point, I agree that people for the most part will drive at a speed that they are comfortable with given road and traffic conditions, regardless of the actual posted speed. Here in Kahleeforneeya, people are in a hurry to get everywhere...zoom, zoom, zoom...Hurry to work, hurry to lunch, hurry home, hurry to the store, etc...and I'm guilty of it myself most of the time.

 

[Chiropteran]

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 used to think like that, but then I thought about it differently.


It seems like about 90% of all drivers speed, in the literal sense. I know most people think of less than 5 over as not speeding, but technically it is still illegal and could be ticketed. Despite that, only a very small percentage of people actually get ticketed daily.

If the government wanted more income from speeding tickets, they could just hire more cops.

 

[sutahz]

With my current car, civic, I dont like to take it over 75. If teh speed limit was 80 I'd go 80. If its 60-70, I wont go over 75. If I had a sports car I'd always go 10 over.

 

[pontifex]

Originally posted by: Chiropteran

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 used to think like that, but then I thought about it differently.


It seems like about 90% of all drivers speed, in the literal sense. I know most people think of less than 5 over as not speeding, but technically it is still illegal and could be ticketed. Despite that, only a very small percentage of people actually get ticketed daily.

If the government wanted more income from speeding tickets, they could just hire more cops.

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.

 

[LS21]

Originally posted by: Chiropteran
If the government wanted more income from speeding tickets, they could just hire more cops.

Yeah, a cop, a patrol car, all benefits, ticketing equipment, beef up courts to handle more cases.... not that easy

 

[Vic]

The answer is firmly no, and this is backed by a gazillion studies, which jagec already explained.

Speed limits can cause people to drive slower than they might otherwise feel comfortable driving, for fear of getting a ticket, but never faster.

 

[Anubis]

Originally posted by: mwmorph

Originally posted by: Anubis

Originally posted by: mwmorph
Up to a point, at some speed, people will be no longer comfortable going any faster. I've done very short stretches at 120+mph when I was stupid and younger. Would I do 120 if the speed limit was 110? Hell no.

I'd say over 85 to 90mph is where 90-95% of drivers will no longer speed further. It's just tiring paying attention and driving well at 95mph for long stretches of freeway. I'd say if you set speed limits of 80mph, you'd be fine with the vast majority of people doing no more than 10 over.

After all, 80mph is just 130km/h which is standard on larger freeways in many foreign countries.

after driving in places where the posted highway speed is 70-75 and driving 80-90
coming back to a posted speed of 65 makes you feel like you are going in slomo

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.

yea it was the same way in boston people woudl be doing almost 100 when it was 55 posted

as i said in my earlier post that in/around cities is an exception

 

[FoBoT]

for most ATOT'ers the answer would be yes, they'll speed as much as they possibly can get away with, if the speed limit was 100 mph , they'd go 115 mph