Automotive question.

[Demon-Xanth]

I've been wondering this for quite some time, they might even be related:

Why do speed limits usually end in 5? 55 and 65 are common, why not just go for 60 and 70?
Also, metric tire sizes are almost always xx5/xxRxx. Is that 5mm really signifigant?

 

[Howard]

Coincidence would be my guess.

 

[Ryan]

THe speed limit on most US highways is 70mph right - at least, the streach of I-10 from Florida to San Antonio has a posted limit of 70.

I deliver pizzas, so I know the speed limit just about everywhere and your theory is pretty much wrong.

 

[JeffreyLebowski]

Originally posted by: rbloedow
THe speed limit on most US highways is 70mph right - at least, the streach of I-10 from Florida to San Antonio has a posted limit of 70.

I deliver pizzas, so I know the speed limit just about everywhere and your theory is pretty much wrong.

Well he might be implying why is it listed in multiples of 5 instead of like 2 or 3????

I think it is because our speedometers are made to show in incriments of 5/10.

 

[Titan]

In the state of VT, most speed limits end in 0. 30, 40, 50. You rarely see a 55, mainly because open roads are 50, due to the turns/hills/ragaved roads. This coming from the state that invented the word "SCARIFIED pavement." And an accurate word it is. In the northeast, interstates are 65. IN NY state, 55 state limit.

I think of the 5 as an extra free buffer you can speed at. If the speed limit ends in 0, you can go 10 over, if it ends in 5, you can go 15 over. I've never been pulled over for 70 in a 55 or 80 in 65.

 

[Mr N8]

In the Midwest, most speed limits seem to be 55 or 65 on highways.

 

[biostud]

We have:
50, 60, 80, 90, 130, but that's km/h

 

[DAGTA]

Originally posted by: rbloedow
THe speed limit on most US highways is 70mph right - at least, the streach of I-10 from Florida to San Antonio has a posted limit of 70.

I deliver pizzas, so I know the speed limit just about everywhere and your theory is pretty much wrong.

He is not wrong. The majority of the US has speed limits ending in 5's. I have driven most of this country. The midwest is almost all 65 or 55. The southwest is mostly 65 or 75. Florida is 75 down I75. Texas has even numbers as does Lousiana when driving over the swamps.

California is mostly 65 or 75. Ohio is only 50 in some parts.

I10 runs from L.A. to Florida. I've driven it from L.A. to Alabama. It is 75 or 65 through California, Arizona, New Mexico, Mississippi, and Alabama. Texas has night speeds that are 5mph slower than the day. So, if the day speed is 70mph in Texas, the night speed is 65mph.

 

[MrScott81]

California likes 5's...
Almost everywhere it's 25,35,45,55,65...then there's the occasional 40, 50 and 70 zones.

 

[lokiju]

Here in south FL I have them both ways, on I-75 its 70 mph, on I-595 its 55mph and on I-95 its 60 mph..

 

[MrScott81]

Originally posted by: DAGTA
California is mostly 65 or 75. Ohio is only 50 in some parts.

I10 runs from L.A. to Florida. I've driven it from L.A. to Alabama. It is 75 or 65 through California, Arizona, New Mexico, Mississippi, and Alabama. Texas has night speeds that are 5mph slower than the day. So, if the day speed is 70mph in Texas, the night speed is 65mph.

California has no speed limit of 75...it's either 65 or 70.

http://www.dmv.ca.gov/pubs/hdbk/pgs19thru22.htm

The maximum speed limit on most California highways is 65 mph. However, for two-lane undivided highways and for vehicles towing trailers, the maximum speed limit is 55 mph, unless posted for a higher speed. On some highways the maximum speed limit is 70 mph, but only if there are signs posted showing 70 mph.

 

[FrustratedUser]

I just multiply by 2 to get an even number.

55 ---> 110
65 ---> 130
75 ---> 150


Problem solved.

 

[Demon-Xanth]

Now only if I could convince the cops to see it that way...

 

[Shyatic]

Actually a study was done in the 70s to measure fuel economy over distance, and they found that 55 was the ideal travelling speed overall, and thus it became the speed limit due to the oil crisis of the 70s.

 

[BatmanNate]

Most of the freeways here are 60. Lots of 40's and 50's in Kent as well.

 

[FrustratedUser]

Originally posted by: Scribe
Actually a study was done in the 70s to measure fuel economy over distance, and they found that 55 was the ideal travelling speed overall, and thus it became the speed limit due to the oil crisis of the 70s.

That's right, the 70's...... I see an early 70's Cadillac with a 500 cui V8 strangled to put out 170hp.
I think it's time to revise the speed limits. Most modern cars are optimised for 110 - 130 km/h (68 - 80 mph).

 

[Kelemvor]

In WI 25, 30, 35, 45, 55, 65 are the most common. Every so often a 40 or 50 crops up. Don't think I've ever seen a 60 in these parts.

 

[duragezic]

I75 in Michigan that goes all the way down to Florida is 70mph. I didn't think many interstate freeways were 75mph.. But where I live there is no freeways, mostly just little one lane each direction highways which are 55mph.

tkotitan2: I don't see how you could not get pulled over for that! Not around here. You would normally think 5 over is okay, but my friend just recently got pulled over for 61 in a 55. Another kid I know got pulled over and was asking the officer why he did, "You were going 27" this was in a 25mph!! Ridiculous.

 

[Demon-Xanth]

Heh, I get my best gas milage at 85MPH. Lately it's been nearly impossible to go more than 60MPH because of people camping out in the fast lane.