Advocacy & Safety - Adaptive bike lane-wide outside lane combination

There are more than a few roads around the greater Seattle area that combine an adaptive, discontinous bike lane/ wide outside lane combination.

The bike lane adaptively becomes a wide outside lane for some intersections, parking lot egress, around rounded gradual corners, etc.

This allows the bicyclist more perceived freedom to move further into the main travel lanes to anticipate encroaches on safe travel, and allows bikes 'into the mix' at areas where a lot of traffic congestion is to be expected as well.

The bike lane stripe provides a clear, demarcated, preferential travel lane that gives the bicyclists their own lane of travel- in some places as wide as a vehicle travel lane. The lane allows bicyclists to pass traffic jams with ease, providing faster and safer bicycle travel than the main travel lanes during heavy commute times.

These 'adaptive' discontinous bike lanes could be a very reasonable way to combine the best qualities of bike lanes AND wide outside lanes on the same road.

They seem to work incredibly well and are well placed on the roads i see them on in the Seattle area.

Hey Bek, haven't you noted that my main concern with BL stripes is their presence approaching at at intersections. Get rid of the stripe 100yrds before every intersection (including side streets and driveways) and you've eliminated 80% of the main practical (vs. political) problem with BLs. Get rid of all stripes on 25mph and less roads and you've eliminated another 10% of the problem.

The last 10% (i.e. on higher speed intersectionless roads) I'll leave up to others to debate.

Al

do you really need 100 YARDS to negotiate a safe lane position?

What kind of tires do you need on one of those?

What kind of tires do you need on one of those?


ROFL.

Dammit I just almost spit coffee all over my monitor.

-D

do you really need 100 YARDS to negotiate a safe lane position?
Definitely for roads with speeds >35mph. Sometimes one uses more, sometimes less.

Al

What kind of tires do you need on one of those?
I fear that the constant crossing of those razor-sharp edges of the painted bike lane lines would be too much for my new zealand lamb skin tires. Are cashmere roads too much to ask for?

weel, that's the first time I've heard of the 300 foot rule for safe lane negotiation, Al.

Anyway, these adaptive bicycle accomodations seems to provide some good aspects of both bike lanes AND wide outside lanes.

weel, that's the first time I've heard of the 300 foot rule for safe lane negotiation, Al.

Anyway, these adaptive bicycle accomodations seems to provide some good aspects of both bike lanes AND wide outside lanes.
It's not a rule, its a suggestion and its one I've made a number of times over the last year and a distance whos length has been debated in some of the BL threads.

I think 100yrds. is a good starting point, a 20mph cyclist will cover that distance in ~10s, a motor vehicle in half that. The full 100yrds distance may also not be available for merging due to lines of stopped traffic.

Perhaps 100yrds is a bit too short, which means its a good starting proposal: End BL stripe at minimum 100yrds before every intersection on 30mph+ roads (and roads at less than 30mph shouldn't have BLs at all)

ya, that's more than a little unrealistic.

these adaptive lanes seem to work fine with breaks in the lane stripe starting at a sixth that distance. Certainly adapting these adaptive lanes to fit local road way demands makes sense, but a blanket 100 yard rule sounds like you're trying to emergency land a cessna, not make subtle lane position changes on a bike.

ya, that's more than a little unrealistic.

these adaptive lanes seem to work fine with breaks in the lane stripe starting at a sixth that distance. Certainly adapting these adaptive lanes to fit local road way demands makes sense, but a blanket 100 yard rule sounds like you're trying to emergency land a cessna, not make subtle lane position changes on a bike.
Have you really spent any time riding in traffic where there are intersections? Just this morning I used ~150yrd to merge left in negotiated space to get into center of rightmost-straight lane, then later it took me 1/4mi to merge left across three lanes to make a left turn.

Al

Have you really spent any time riding in traffic where there are intersections? Just this morning I used ~150yrd to merge left in negotiated space to get into center of rightmost-straight lane, then later it took me 1/4mi to merge left across three lanes to make a left turn.

Al

Sounds more like a difference between Arizona and Seattle. Perhaps Arizona needs 100 yd bike lane merge areas and Seattle might not. I believe that this is the point that Bek is trying to make.

Sounds more like a difference between Arizona and Seattle. Perhaps Arizona needs 100 yd bike lane merge areas and Seattle might not. I believe that this is the point that Bek is trying to make.
I really can't believe that Seattle doesnt' have BLs and intersections on >35mph roads. In the cities I know well: Portland, Houston, Boston, San Diego, San Francisco and other have intersections where this would apply. But, yes, I have never been to Seattle.

Al

Um, yes, Seattle has plenty. And not all intersections require a wide outside lane, there are many with dedicated bike lanes right up to the light.

Some intersections the bike lane stripe ends 50 feet and that is enough. On others, it ends a quarter mile out and that seems too far. On some roads (like a major downhill) a quarter mile would be just about right.

But EVERY intersection and driveway doesn't require either an end in the bike lane stripe OR 100 yards of clearance.

This is an adaptive lane concept for things like bus stops, gradual curves in the road, moderate uncontrolled intersections and places where a bicyclist is likely to need more lane space. The adaptive lanes are around things like a senior center driveway, or a bus stop, for example.

This is a little different that negotiating major intersections, which it sounds like Noisebeam is considering? Those are already addressed in traffic planning, these new (to me) adaptive lane is a little bit more subtle and engineered for a bicycle to maintain a

"to the right of overtaking vehicles, to the left of likely trouble areas" position more safely.