PDA

View Full Version : Lane Change Booby Traps on Interstate Highway

Hornblower
2013-Sep-08, 12:28 PM
This is sort of a sequel to my earlier thread about lane discipline and the desirability of keeping right except when passing slower traffic, as is required by law in many places. This can be complicated in heavy traffic by the design of the road. Yesterday I was driving for the first time on a recently rebuilt, "improved" stretch of I-95/495 here in northern Virginia. At some major interchanges what had been a through lane for miles became a right exit only or else pinched off just beyond the exit, requiring a merge to the left with little warning. In other places a far left lane would do the same thing, requiring a quick merge to the right. Sometimes it seemed that I had changed lanes to the left to avoid a right-exit-only situation, only to have that lane become a left-exit-only with new through lanes created on the right for traffic coming in from the previous interchange. This may be justified by elegant mathematical algorithms used by the engineers on the basis of predicted volumes of traffic on the various routes, but it appears to break down in heavy traffic when impatient tailgaters bunch up and make lane changing difficult.

DonM435
2013-Sep-08, 06:41 PM
I did my first serious driving in Atlanta, Georgia, and was later to learn that the interstates through there were notorious for disappearing lanes. I thus developed a habit of staying in the middle when possible.

It didn't help that for some (antebellum?) reason all of the streets were named "Peachtree" there.

Nicolas
2013-Sep-08, 07:30 PM
Portugal is filled with 2 lane roads where the right lane disappears every other kilometer. Stay focused!

Glom
2013-Sep-08, 10:57 PM
We have increasing numbers of lane drops at junctions as our roads get widened. They're annoying.

On M3/M25 junction, the M3 southbound the nearside lane diverges for the junction and shortly after, the offside lane merges leaving only one lane through the junction. This is a very strange arrangement, but it exists so that two lanes of M25 traffic can join the M3. The M25 is London's ring road and very busy while the M3 is the main route from London to Southampton. Because the M3 ends shortly inside the M25 and the connections to it from central London aren't great, the bit inside is relatively lightly trafficked, while the section outside is full of traffic travelling between London and commuter belt towns. In this way, the M25 is a far bigger supplier of traffic to the southbound M3 than its own upstream.

neilzero
2013-Sep-09, 01:14 AM
I also find one of the middle lanes is best in and near Jacksonville, Florida, for both interstate and multilaned local streets. Right turn on red in Florida, means frequent speed changes in the right lane, less so in other lanes. Right turn on red also means the cars behind me cannot turn right on red if I am waiting for a green light in the right lane as I want to go straight.
We recently added at least 4 places where there is no option for staying on I295 after about a mile of driving in the right lane. Concrete barriers assure that you are off the interstate. In heavy traffic making a U turn is dangerous if not illegal. Neil

NEOWatcher
2013-Sep-09, 04:42 PM
Lanes? What lanes?
I just drive between the orange barrels.

danscope
2013-Sep-09, 07:00 PM
Such practices as we see (and noted above) would be easier if they would have suffient signs early enough to warn you.
Sometimes, people even steal the signs ... just for fun, to vex the spirit. And yes, things keep changing.
The tailgaiters make life impossible.

Githyanki
2013-Sep-09, 08:26 PM
Sorry, never drove in West Falls, but I took the bus and the train at West Falls Church.

Hornblower
2013-Sep-10, 02:35 AM
When I think about it a bit more, I can imagine that these shifting lane patterns may actually reduce the total amount of merging that is needed when the traffic is really heavy, depending on the relative amounts of traffic on the various routes. I do think it makes any mandatory keeping to the right except when passing impractical in such traffic patterns. I generally stay in the middle when there are three or more lanes, and I don't want to move over into a lane that is about to become exit-only to get out of the way of a speeder coming up behind me. Such a rule only makes sense when the lanes in question are continuous over long distances, which is the way I-95 and I-495 were before the recent rebuilding.

Hornblower
2013-Sep-10, 02:43 AM
Sorry, never drove in West Falls, but I took the bus and the train at West Falls Church.This is off-topic, but your post made me think of a time I fell asleep on a westbound train and overshot East Falls Church, where my car was parked. I rode on to West Falls Church and stood on the platform at least 20 minutes before an eastbound train came along to get me back. I probably could have walked back in less time.

Hornblower
2013-Sep-12, 04:35 PM
What really is spooky for me on these rebuilt and “improved” freeways is keeping my bearings on I-95 northbound south of the Capital Beltway, which is I-495. Here I am haunted by a lifetime of memories of the original lane configurations, in which I-95 went straight into Washington, and a simple right exit ramp took us to the Beltway to bypass Washington and head for Baltimore and points north and east. Now we have to counterintuitively keep left to get to the ramp that goes right to that segment of the Beltway.

Some history here: In the 1950s, as I was learning my way around Washington and vicinity as an inquisitive child, we had Virginia highway 350, a limited access superhighway built during World War II. It was named Henry G. Shirley Memorial Highway, or Shirley Highway for short, and provided a fast nonstop route into Washington for the final 20 miles from Richmond and points south. With the advent of the Interstate Highway system it became part of I-95. Construction of the Beltway, which had been envisioned as a bypass as early as 1932, started about 1958 and by 1964 it was open in a complete circle around Washington, about 10 miles out from downtown.

In the meantime an extensive network of freeways inside Washington DC, which would have devastated a lot of residential areas of the inner city, were cancelled in the face of massive public opposition. One of these, the North Central Freeway, would have completed the route of I-95 through the center of town. In response to this, the highway authorities redesignated the south and east half of the Beltway as I-95, as it had evolved into the primary route for long-distance traffic between New York and places south of Washington. The part of Shirley Highway inside the Beltway became I-395, and it appears that the officials were now thinking of that as an exit onto a secondary road, when physically it still was a very direct route into Washington for motorists coming north on I-95 from points south. This may explain the goofy layout where we have to keep left to go right on the Beltway while bearing right to go left on the Beltway.

In my opinion there really are no "primary" or "secondary" routes here. All freeway routes are heavily used by motorists going from everywhere to everywhere, with most of it being local. The officials belatedly renamed the southeast side of the Beltway as combined I-95/495, and there are express toll lanes being added on stretches other than the combined section.