check my arithmetic please
 

I'm a solo bicyclist, never been a Lance wannabe so haters can move on.

I may need to make a presentation to my town council regarding "sharing the road".
Most drivers are very good at sharing but nearly all take chances when passing me.

They ALL cross over the midline in an abundance of caution even though I am always inside the fogline but some do so on curves :eek:.

I have been scolded more than once even had a few objects hurled at me but that's in the very small minority.

I've requested an appearance in order to ask that I be permitted to post a letter on the township website. Part of that memo is a calculation of how long it actually takes to pass me. I posit that there's no need to endanger themselves by crossing the line, they only need to slow down and make the pass.

Here's the math; t= Da + Db / Sa - Sb; units are D= feet, S = feet/sec

If a car starts to pass me at Da = 30 feet behind and resumes normal travel at Db = 20 feet ahead all at S1 = 25 mph and my speed is S2 = 10 mph then it would take the car 2.3 sec to pass me.

Did I get that correct?

The premise is wrong. Cars accelerate.

Lot's of cyclists on this island. Many think they are Lance Armstrong, and are not holding up traffic. Some use the shoulder, and some drivers will still not pass for fear that the cyclists will pop back on to the road. Other drivers go wide into the oncoming lane. I damn ear got hit by some driver doing this when I walked to the edge of the road to check the mail. (not expecting someone hauling ass in the opposite lane as they pass ridiculously wide a cyclist. )

Back to your linear math.. your Da and Db are rather generous assumptions.

I get the same number (~2.273 seconds traversing 50 feet at 15 mph observable speed difference with no relative acceleration).

Am also a mostly-solo cyclist; used to cycle primarily for transportation and secondly for enjoyment. I've all but given up commuting due to traffic issues near where I live.

Couple of thoughts for your letter:

- Explain what you do to make yourself visible to others.

- Also explain how you maintain your own situational awareness when riding (how do you know a vehicle is behind you).

- Explain how you try to ride in a fashion to not be an obstacle and have a safe way out of a possible vehicle encounter.

When I used to provide coaching to others for riding in traffic, the mantra was "Visible - Predictable - Defensible". Always be seen. Always ride predictably so drivers know what to expect. Always have a way out of every situation (a place to swerve/ditch to avoid getting hit by a car).

Good luck.

Island: All of that can be adjusted. I am mathematically deficient when it comes to developing an equation so I thought it simpler to start with steady state velocities.

Good stuff thanks.

Yes, your math checks out for simple math of velocity = distance / time. (therefore; time = distance / velocity) ...and as you have it you look at the the set distance of need passing length of 50' and a relative speed difference of 15mph. This is the same as saying someone is stopped on their bike and a car is passing at 15 mph. ...and needs 50 ft to do so. ...and saying that the pass event is not over until the car is 20' past the cyclist on the side of the road.

Some people do take that much space. Many others don't.

Well, assuming an ambient temp of 20C, with barometric pressure at 29.92 hg, and factoring in the drag and friction coefficients, along with compensation for Coriolis, I get 2.85744 seconds. :p

I’ve ridden a bike a fair amount over the years. Including in NYC - so I know a bit about doing it traffic.

I always give cyclists extra space when I pass. Mainly because I know how disruptive it can be when a truck - which I drive - barrels past. The wind from it can be enough to move the bike - which can be disconcerting if you aren’t expecting it.

No one, anywhere is going to slow down if they can pass you. Expecting them to do so is - imo - adopting a very rosy view of humanity interacting with one another.

Be happy they give you the courtesy of space.

Just buy a middle finger front and rear reflector and go on about life. Might consider some better padding for when the objects get thrown tho.

25 years ago cycling was scarier. Not nearly as many bikes on the road and drivers weren't so used to us. Most still hate bikes on public roads but are forced to deal with it. We can thank Lance for popularizing the sport like Tiger for golf but as role models? Uh, no

Are you the only cyclist in town? Having a letter on the website would apply only to you? Or are you intending to speak and modify behavior of all other cycles on the road?

I don't get the slow down to pass part. Shouldn't you pass a bike just like you would a car?
Here the law is 36" between the car and the bike

as an ex cyclist all I asked for is a little respect and don't hit me or harass me.

it seems like when you get on a bicycle you are treated worse than a child rapist.

what gets me is someone can drive a golf cart on the road and they are left alone, I could ride faster than golf carts and I was easier to pass.
nothing like being behind a golf cart going 20-25mph on a 35 or even 45 mph road and you cant pass them

My point, which I didn't emphasize is that the cars ALWAYS cross over the double yellow while accelerating. If they just chill and pass slowly without leaving the lane, even at 25 mph it'd only take a few seconds to pass me and no one need be endangered. Keep in mind that I ride roads that aren't heavily traveled but enough so that such maneuvers are risky.

This lands in a "grey" area. I believe in CA cars are not supposed to cross a double yellow line (DYL) to pass. However, if they have a clear line of sight then they can/do cross and give you extra or at least enough room. In CA the room is 3 feet from the most outside part of the bike. I would rather they cross the line and give me extra room. We have some popular cycling roads around here that are narrow (no shoulder). On a right direction curve with limited visibility the situation becomes dangerous. If you are cycling and hear a car coming you need to get over (even stop) or risk getting hit. Since many drivers over-drive their sight - they can't stop or slow down in time. The car doesn't want to cross the DYL at that point because there is not an adequate line of sight. Car drivers come in all shapes and sizes - some don't like cyclists and have limited defensive driving skills. If you are riding a bike you are vulnerable. I don't see why calculating a passing time is relevant.