I’ve never paid close attention, but I always thought they were a Chicagoland thing. I can’t think of coming across anything called an “oasis” anywhere outside the tollways here. An oasis–at least how I know the term–is a specific kind of rest stop that spans the highway from one side to other, so traffic from both directions has access to the same businesses.
The Illinois system is unique in that they built the restaurants on a bridge across the roadway, (so they only had to build one each of each restaurant). As far as I know, “oasis” is used only for the Illinois and Indiana toll road rest stops.
If you look at pulykamell’s second link, you can pull back from the photograph to see the entire rest stop.
zoid, notice how the parking for each side is separate? They still adhere to the convention that traffic will exit from the right lane and enter from the right lane. In order to allow crossovers/U-turns, they would have had to build an additional bridge that would support traffic. (And then they would face the same problem of collecting all the toll revenue that they wanted from those stretches of highway.)
ETA: While called “oasis,” the Indiana rest stops are built on the more typical layout of having the restaurants and gas stations duplicated for each direction of traffic.
Can you explain what you mean? There’s an overpass, but there’s a big ol’ building on it, not a road.
[quote=“pulykamell, post:16, topic:643476”]
I’m having a difficult time visualizing an oasis like this. The ones I’m familiar with here in the Chicago area only have a building in the middle, at least as far as the ones I can remember. They’d have to build an entire road to access the other side. Am I not understanding the question correctly, or are there other oases?
Like, look here. I don’t think I understand exactly what you’re trying to describe.
Very much like the one in your link is what I’m thinking. If you can build a damn building spanning the gap a few lanes should be a snap.
An oasis is only on the toll roads because they are limited access roads. There are no interchanges where you can develop businesses. They are usually a large conglomerate of fuel and food court and there is only access for the direction you are traveling.
Rest stops, on the other hand, are on standard interstate highways mostly including a bathroom and maybe snack/soda machines.
I was going to say “because all the camels tied up to the palm trees make it too complicated,” but that would imply that in order to leave the oasis, you’d have to back out (and everyone knows that you can’t make a camel back up).
Must learn to type faster.
Actually, according to this, there is one oasis on the Tollway system that does not have the “bridge restaurant” building: the Dekalb oasis, and that does allow turnarounds.
As a Chicagoan, I don’t use the term “oasis” generically for all rest stops. Just those that are called as such. Otherwise, it’s just a “rest stop.”
That’s not the same as the remote, rural rest stops.
In the environments, like the Chicago oases (and yes, I am quite familiar with those), the overpass/bridge was designed for pedestrian traffic and restaurants, not automobiles and trucks. Under what circumstances do you envision a frequent cross-traffic? Enough to justify the added expense of more construction? That’s not what the oases were intended for.
Think about it this way. You build a “service area” for gas and food, but since cars going either direction will have the same needs, you can build a structure that serves both sides at once. You aren’t building a place to turn around; there are other places for that, where turning around and going in other directions are combined. An oasis or a rest stop is just a wide spot in the road.
I think Ethilrist’s initial answer is the best one. It doesn’t seem to be a trivial task to me, and, moreso, a waste of money. How often does one need to turnaround at an oasis anyway? I can’t remember a single time when I’ve ever needed to do that, and I use the tollways frequently.
I don’t think it does allow turnarounds-
which sounds like it might be what **zoid **meant by
A building that spans the road doesn’t have significant dynamic (moving) loads. A road bridge does. Plus, to safely allow traffic to exit, climb to the bridge level, cross, go down to ground level, and safely rejoin traffic would require much more space, much more construction, and make things much more complicated. Two parking areas and some stairs/elevators is much simpler than a roadway.
But most of that already exists, traffic already has to (as you said), “safely allow traffic to exit, climb to the bridge level, cross, go down to ground level, and safely rejoin traffic” just without the crossing part. All you have to do is add the cross.
OK, so it seems like:
[ul] [li]it’s not in the best interest of the tollway authority to allow people to escape tolls[/li][li]it would add significant construction cost to the oasis structure [/ul][/li]
Would it be possible to allow crossing for a semi-significant fee?
The fee would probably need to be more significant than anyone would be willing to pay to avoid driving to the next exit. I don’t know how often people miss their exit at a location where they will come upon an oasis before the next exit, but it’s probably more common to arrive at the next exit before an oasis since there are apparently only 7 or so oases in the state. And IME, it’s not all that common to miss an exit on a tolled road - I miss turns on local streets and exits on highways within NYC all the time, but not only have I never missed an exit on a tolled road , I’ve only once in 30 years been in a car where someone else did.
Fine, I’m a dumb-ass 
Hmm…I just had a quick look from the overhead, and it seemed like it did let you, but on closer inspection it appears that’s right. I’ve never actually been at that oasis, though, and it is unique in its design.
This service area on the Pennsylvania Turnpike has what’s basically one big parking lot, but there’s still a fence dividing everything in two to keep people from turning around.
According to your link, there are just seven of them, all on the Illinois Toll Highway system.
Nor had I (lving in Australia). This whole thread has been a very confusing read, to say the least.
It’s because for every motorist who misses their exit and would be aided by this arrangement there are fifty who would inadvertently change their direction of travel and have to figure out a way back. It’s a blessing, really. You can’t do it because so many of you would bollix it up. Don’t try to deny it, I’ve seen you drive.