Lane sharing: max speed?

[Spidey]

I lane share at any speed where I'm comfy doing so.  But I always hear people saying (or writing) that they don't lane share about ___ mph.  Sometimes it's 30, sometimes it's 50, but it's a pretty common statement. 

Can someone explain the "don't share above a certain speed" rationale to me?  

[Speeddog]

Purportedly the 'official' numbers are not more than 20mph over what traffic is doing, and not more than 40mph in any case.
Dunno where I heard that, probably from Traffic School a zillion years ago.

I've found those numbers pretty much match my 'alarm threshold'.

A car going 20mph can change lanes pretty rapidly, or at least block the gap.



Some marginally helpful references:
http://dmv.ca.gov/pubs/hdbk/shr_slow_veh.htm
http://en.wikipedia.org/wiki/Lane_splitting

[ScottRNelson]

My own upper limit is when I feel the need to shift up beyond second gear.  That's somewhere between 20 and 30 mph and time to merge back in with traffic.  And my concern is not just how quickly others can change lanes but also how much off course I could get if I were to hit someone or something.

When I'm commuting back to Pleasanton on my KTM (on non-rainy days) and get to the turn on I-680 in Fremont where it switches from north to east heading over the Sunol grade, there are normally several miles of splitting through there.  I'll keep up with the other riders until the slow traffic starts speeding up, then the other riders will get away every time because I don't feel safe splitting as fast as many of them are willing to go.  I think they're putting too much trust in the drivers doing the right thing.  I always ride assuming that others will do the stupidest possible thing and I do all that I can to make it difficult for them to take me out when they do it.

I also won't pass other cars at more than about a 10 mph speed difference.  I'll occasionally see riders (when in my car) going quite a bit faster than that.  When I'm checking to make a lane change, I'm not looking back far enough to see anybody closing at 40 mph, and I'm much more careful at checking than most drivers, plus I always signal before making the lane change.  I'm still concerned that one of the fast splitters might hit me anyway, even though I've done my best to check for a clear merge opportunity.  It will be their fault, but I'll still feel bad about getting hit by one of them.

[Gimpy]

For me its all about closing speed. I've been guilty of making the statement  "I'm not comfortable of lane sharing above (x) MPH." In retrospect I was really just trying to put a number to my comfy level.  In truth its only half the statement.  It should be; "I'm not comfortable lane sharing at (x) speed when traffic is going (y)".  20mph above what traffic is doing sounds about right.  I dunno about topping out at 40mph. 

As far as whats legal, I've always assumed that it was up to the LEOs subjective discretion of what a reasonable safe speed is, so I try not to scream by police cruisers.  Never been pulled over, so I must be doing something right. 

[ScottRNelson]

20mph above what traffic is doing sounds about right.  I dunno about topping out at 40mph. 

You obviously have a much higher threshold than I do.  I'm certain that I wouldn't be able to react in time to a sudden lane changer if I were going 20 mph faster than them.  I'm not willing to take the risk.

[lemond]

I only lane split when filtering thru stuck or congested traffic. when the traffic starts moving again at 20 and above I get into my own space and lane. splitting between fast moving traffic is too dangerous for my taste

[Scotzman]

I will typically split if traffic is moving 10+ under the speed limit.

[red baron]

I make a habit of getting myself out of the way from getting rear ended by a cell phone toting idiot. Always make my way to the front at lights also. Often I let the cars in front take off first and then file in and see what they're speed is like.

[mendoje]

+1

I ride mostly recreationally now, but 20 years ago I used to commute to work, go everywhere and run nearly all my errands on my motorcycle.  I recall many motorcyclists on the freeway followed this approach to some degree.  Today, it seems most riders are now rocketing between lanes during rush hour.  It's only a matter of time when lane splitting will be outlawed for civilians in California, all because of these idiots!  If that happens, what will be the point of riding a motorcycle, in California rush hour is several hours long, every day of week, and conjested traffic can crop up anywhere!

I only lane split when filtering thru stuck or congested traffic. when the traffic starts moving again at 20 and above I get into my own space and lane. splitting between fast moving traffic is too dangerous for my taste

[El Matador]

I only lane split when filtering thru stuck or congested traffic. when the traffic starts moving again at 20 and above I get into my own space and lane. splitting between fast moving traffic is too dangerous for my taste

Interesting. I'm a lot more nervous whilst splitting lanes in slow moving traffic. The operative word here being moving. I find that it is in these situations when drivers will "jerk" into the next lane violently to try to move into a faster moving lane and as such are more unpredictable. I find it easier to read drivers who are moving at a faster rate of speed.

[Drunken Monkey]

I'll split at any speed up to and above the speed limit but never more than 10 MPH faster than cars are going.

With one caveat: I never split faster than 30 when the cars have open spots next to them as in my mind there's too much chance of a lane change and at those speeds the cars are going fast enough that it could occur suddenly.

Worst place to split is when there's a gap in traffic and a high speed differential between lanes. High chance that some impatient numbnuts will decide he wants the open space and crunch you.

[DarkStaR]

I'm guessing about anywhere from +5 to +15 than the flow depending on congestion.

Another question: 

What (fwy) lanes will you split between?

Of course I mostly split between the 1 and 2; however, if I don't feel safe where I am, I'll split between any lanes for a short period of time to get the F' outa there.

[Speeddog]

Freeway, virtually always just between lanes 1 and 2.

Echoing DM's comment.... I don't split between lanes that have an appreciable speed differential.

[live2ride]

I always ride assuming that others will do the stupidest possible thing and I do all that I can to make it difficult for them to take me out when they do it.

this.