[dcomiskey]

I'm sure it has to do with drainage, but I am amazed that nearly every exit ramp is off-caber to the OUTSIDE of the curve. In bad conditions, this only leads to more likelihood that a car will go off the road if hitting that curve too fast. Why aren't they designed like race track curves with decent banking?
Also, there are plenty of curves on Parkways (the Merritt is a perfect example, esp that big curve in Greenwich by the reservoir) that follow this design as well.

Am I missing something or are traffic engineers as stupid as I think?

 

[LSinLV]

Re: Enlighten me - why are most exit ramps off-camber? (dcomiskey)

that's a roadway engineer's way of SLOWING YOU down??!!!

Most of the curved off-ramps here in the SW are correctly cambered for the turn, and those are the one's (at least here in Vegas) where idiots are flipping thier cars, trying to exit/enter the freeway too fast... http://****************.com/smile/emthdown.gif

 

[WOT]

Re: Enlighten me - why are most exit ramps off-camber? (lsinlv)

yeah the only time I see a exit ramp thats not level is when its banked, never an off camber one. where are you seeing this?

 

[dcomiskey]

Re: Enlighten me - why are most exit ramps off-camber? (WOT)

Quote, originally posted by WOT »

yeah the only time I see a exit ramp thats not level is when its banked, never an off camber one. where are you seeing this?

East coast. Everywhere.

 

[climacus]

Re: Enlighten me - why are most exit ramps off-camber? (WOT)

I can honestly say I have never seen an off-camber off-ramp. The worst I've seen are non-cambered ones, and people instinctively slow down *a lot* when they see those kinds of off-ramp (well, the posted limit is also substantially lower at those ramps). I can't even imagine the kind of carnage that takes place at an off-camber off-ramp.

 

[Robin]

Re: Enlighten me - why are most exit ramps off-camber? (WOT)

I've always wondered the same thing. In the DC area, every exit ramp is off camber. I figured it was either drainage or 'safety' reasons. Whatever reason, it sucks.
-R

 

[dcomiskey]

Re: Enlighten me - why are most exit ramps off-camber? (Robin)

Well, for anyone who lives around here, exit 40 for Route 7 north off the Merritt is a perfect example.
Also, the ramp ON to I-95 North from Route 7 south is this way also.

 

[AKADriver]

Re: Enlighten me - why are most exit ramps off-camber? (dcomiskey)

Most of the ones I see are not only off-camber, but reducing radius

 

[dj_wawa]

Re: Enlighten me - why are most exit ramps off-camber? (AKADriver)

uugh, decreasing radius kills me, seriously, it's so.. scary/frustrating when you go in a smidgeon too fast

 

[m1]

Re: Enlighten me - why are most exit ramps off-camber? (dj_wawa)

yeah, i've driven on a few off camber, decreasing radius ones...good lord those are scary

 

[johnroche]

Re: Enlighten me - why are most exit ramps off-camber? (dj_wawa)

the rte 7. south to 95 N one.... if i remember correctly, has both directions of travel in it. therefore it is correctly banked for one direction. As a civil engineer I wish i could tell you why they arent banked in different ways, but that is at least an explanation (assuming I remember correctly)

 

[GRVR6]

Re: Enlighten me - why are most exit ramps off-camber? (johnroche)

I cannot think of one off- camber ramp.

 

[nuxx]

The design of off camber, no camber, and especially reducing radius ramps makes sense from a safety enforcement point of view. While the first helps with drainage, all three make it extremely easy to determine if a person was progressing the ramp at excessive speed.
Many people travel ramps based on the speed of the person in front of them, which can be a bad mistake. I remember watching an Explorer slide into the ice plants from a decreasing radius off ramp, because he was trying to pace the road race prepped 300ZX TT I was riding in.

 

[climacus]

Re: Enlighten me - why are most exit ramps off-camber? (johnroche)

Quote, originally posted by johnroche »

if i remember correctly, has both directions of travel in it. therefore it is correctly banked for one direction.

Why should directions of travel matter? A correctly cambered road increases grip in both directions (think about the Indianapolis speedway, NASCAR and F1 run in opposite direction, but the effects on grip is the same). Unless you mean the outside lanes actually fall off after peaking at the center divider.
You guys must have some poor ass highways. I've never seen an off-camber ramp here, even out in the boonies. I hope there are rails on the outside of these ramps.

 

[TBT-Syncro]

Re: Enlighten me - why are most exit ramps off-camber? (dcomiskey)

I wonder if it's to increase sight-lines.

 

[slugman]

Re: Enlighten me - why are most exit ramps off-camber? (johnroche)

Hmm, I should ask my dad who was a civil engineer with CT DOT for umm 30 years till he retired last year, though he dealt more with bridges I think. I enjoyed one bit he told me (slightly tongue in cheek) about some of the frustrations with any road design/improvement being that anything they designed would take 20 years before it was actually built, at which point it was horribly out of date for the speeds, capabilities, and numbers of cars on the road when done. There are also cases where even simple road improvements were blocked due to land issues, or to save a particular type of mosquito that liked the bank of a road, or just towns that wanted to maintain a quaint atmosphere (and the resultant backed up traffic) so it wasn't allowed to be expanded even with a bunch of deadly accidents every year.
Though I'm not speaking for the DOT or my dad really, I enjoy scaring passengers on those decreasing radius turns, they're one of the main reasons I modify my car. I have noticed that 95 east of New Haven (lived there for a few years), and rt66 from 91 into Middletown (where I grew up) are finally being expanded, which the state has been pushing for forever.
-slug

 

[VW Lou]

Re: (nuxx)

Quote, originally posted by nuxx »

Many people travel ramps based on the speed of the person in front of them, which can be a bad mistake.

yep, and it's a really bad mistake when they are following me in my Vette. heeheehee

 

[Jetta_1.8Tip]

Re: Enlighten me - why are most exit ramps off-camber? (AKADriver)

Quote, originally posted by AKADriver »

Most of the ones I see are not only off-camber, but reducing radius

Heh, yeah those can sneak up on ya sometimes. They'll sharpen it up real hard right at the end when you are about to go straight again to merge or something. I think their designs are based on 50's car handling

Heh... keep in mind that most of the interstates were designed and built in the 40's, 50's and some 60's so I guess they are spot on!!

 

[The Apple]

Re: Enlighten me - why are most exit ramps off-camber? (dcomiskey)

I've never seen an off-camber ramp in my life, all the ones down here in FL tilt inward. In fact if someone told me they acctualy make off-camber ramps I'd have a hard time believing it, save for this thread.

 

[jacobyb]

Re: Enlighten me - why are most exit ramps off-camber? (The Apple)

Every curved off-ramp here is banked. This is for drainage and for people that get a small case of speed blindness when exiting a freeway. they take a bit too much speed into the off-ramp and the banking helps them to scrub it off without an accident. It also keeps the water from building up so that when cars exit they don't hydroplane.