Quote:
Originally Posted by cabotp
The intersection at Hwy 17 and 91 connector is definetly flawed. Although I don't believe the interection is 100% to blame for the roll overs. That the driver's of the tractor-trailers are also to blame for flipping their vehicles as well.
The problem as mentioned before is that the road leans with the turn not against the turn. This is most evident when going WB 17 to SB 91 connector. And hence why most of the roll overs happened on that turn.
Most intersections are flat. And every driver whether it is a smart car or motor cyclist or a tractor trailer with 2 trailers. Will learn what kind of speed their vehicle can handle at a "normal" interesection. So lets say X speed is that speed.
Now a driver comes along and approaches the intersection at 17 and 91 connector. Maybe it is there first time. They want to make the light so they push the speed a bit. What happens though is they flip. Since that intersection can't handle a speed of X like other intersections can.
Which is why I put part of the blame on the driver's and the other part on the intersection desigh. Since they have put up the signs warning driver's drivers to slow down as their a potentional to tip. Suddenly I have not heard of any flipped tractor trailers at that intersection. Maybe because now the drivers are approaching it at a snails pace and just slowly rolling through and keeping their speed to a very minimum.
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It's also going the other way. From the 91 connector to WB 17 (making the right turn). The turn is controlled by a light; no right turn on red light. So I see a lot of drivers try to beat the light. The road does slope a bit away from the turn, so a truck trying to beat the light and driving too fast can flip easily. Or if he decides last second he can't make and slams on the breaks, it's a pretty easy jackknife. I've also seen cars and trucks ignore the light and treat it like a merge (not even a yield), forcing traffic on the SFPR to swerve.
As for the rest of the SFPR: it's amazing. The speed limit could easily be 100km/h on most of the road (and most cars already go faster than that). The original highway 17 had a speed of 90km/h through Ladner, and the SFPR has shoulders slightly larger than it had. The SFPR also has amazing sight lines for being a road with many turns. A higher speed would be perfectly safe. I would say 100km/h for cars, and 90km/h for trucks, with slower sections around the Pattullo and 104 Ave.
But I won't be surprised if the 91 Connector is upgraded to full interchanged ASAP. Even without the accidents, during the AM peak, traffic on WB 17 turning left onto the connector will back up past the left turn lane into the passing lane almost every day. The preloading is there, they just need to start work. They should work on 72nd Ave and the 91 connector at the same time as part of the same project.
Also, does anyone know what they are doing between Tsawwassen Drive and 56 St.? It looks like they are widening it, but it is hard to tell how wide it will be. I'm hoping it is a full 2 lanes WB and 3 lanes EB when it is done. 4 EB lanes would be nice, because during the PM peak, 2 ferries arrive between 4:30 and 5pm every day, and there will be a lot of mall traffic.
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-- what I'm suggesting / criticizing about the project is that if they wanted to post it at 80km/hr, it should have at least had a 90km/hr design speed, given GVRD drivers all push the speed limit 10-20km/hr on a regular basis. That aside, yes, the at-grade intersections are a huge problem with this road, and I've been vocal about that since it was first leaked that they were being downgraded from interchanges... but is there not some concern about an improperly banked curve at the Nordel Way Connector? Or for truck rollover potential on the steep hill coming down SFPR from Hwy 1 where there is a curve near the bottom of a hill? Trivial to cars, but serious problems for truck drivers who may be running late, or simply aren't familiar with the road. Both of these problems could probably be 'band-aided' with some yellow cautionary 'curve ahead, go 60' signs -- but definitely not the entire route at 60! 
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