CityCyclingEdinburgh Forum » Computers, GPS, 'Smart' 'Phones

The close passometer

(16 posts)

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  1. tk
    Member

    After cycling to Gullane and back a few weeks ago and having so many vehicles passing too close I'm thinking of creating a close passometer to measure and record the experiences.

    Something along the lines of a raspberry pi, two cameras to give a forward and reverse image (ideally with overlapping coverage) and some means of distance measurement. Possibly also a handlebar button to log other scary moments

    Think it would be fascinating to see a graph of how close cars come along with the video footage

    Posted 7 years ago #
  2. acsimpson
    Member

    Sounds like an interesting project. You could even market the kit once you've got it all setup.

    A quick google search suggest that you can pick up an "HC-SR04 Distance Measuring Transducer Sensor Ultrasonic Module for MCU" for very little money but the harder part might be writing the scripts to get it working.

    Posted 7 years ago #
  3. duncans
    Member

    If you have the budget, this is the toy to get:

    Laser ranging module

    Been thinking about it, but that is a bit spendy.

    Posted 7 years ago #
  4. Roibeard
    Member

    Might be worth contacting Ian Walker as they built something for their passing studies (~2007):

    http://drianwalker.com/overtaking/

    Actually, just spotted that he published plans for building an overtaking sensor a couple of years ago:

    http://drianwalker.com/overtaking/buildasensor.html

    Features an Arduino Uno rather than a Raspberry Pi, but similar.

    Robert

    Posted 7 years ago #
  5. neddie
    Member

    @tk

    I can probably get you some ST laser ranging devices, once I get back from hols on Monday, if interested.

    Posted 7 years ago #
  6. amir
    Member

    That's an interesting study. You can download the data.

    An useful query to resolve is where the passing distance is measured from - the middle of the bike? It may say in the full journal article but I don't have free access. The article about building a sensor implies it's on the rack.

    It might be interesting to work out how many pass at a safe distance. Some countries seek 1m or 1.5m distances depending on speed. I'd like to interpret that as the distance from the outside rather the middle. Let's say the distance from the middle to the outside (e.g. shoulder/elbow) is about 30cm. Then we have "safe" distances of 1.30m and 1.80m.

    In the data set of 2355 records, 581 or 25% are within 1.30 m and 1778 or 75% are within 1.8m. However only 171 records were main or rural roads.

    Are there any other studies of a similar nature?

    Posted 7 years ago #
  7. Roibeard
    Member

    @amir - are you sure you don't have access?

    Try this link for those with an EASE account:

    http://www.sciencedirect.com.ezproxy.is.ed.ac.uk/science/article/pii/S0001457506001540

    There have been a few different studies building on the Walker work, both in the UK and the US, and a citation search for this study will lead you down the rabbit hole...

    Worth also looking at his more recent work, reported on here:

    http://www.bath.ac.uk/news/2013/11/26/overtaking-cyclists/

    Robert

    Posted 7 years ago #
  8. amir
    Member

    @roibeard - I only work at the Uni not for it - so I don't have access

    Posted 7 years ago #
  9. amir
    Member

    In the more recent paper that Roibeard posted, the distance is clarified:

    "After data collection was complete, a constant was subtracted from all the readings so each measurement
    gave the distance between the passing vehicles and the outermost point of the bicycle’s handlebars,
    rather than the sensor itself. "

    Posted 7 years ago #
  10. friskiffla
    Member

    If you can also point one at the ground in front of the bike to measure the potholes, and have it automatically log them on fixmystreet, then that would be doubly handy

    Posted 7 years ago #
  11. slowcoach
    Member

    "A UK-based research team is developing 'smart scanning' technology to detect the early signs of potholes ..." (before they become dangerous?) a bit heavy for on a bike though.

    Posted 7 years ago #
  12. dougal
    Member

    Since potholes always appear in the same place it shouldn't be difficult to predict where they'll appear again - wherever heavy vehicle accelerate (eg bus stops, corners in bus lanes) seems the prime spot.

    Posted 7 years ago #
  13. slowcoach
    Member

    Other prime spots include failed joints or re-instatements after utility works etc and collapsed gullies. If the road is built/repaired properly, the potholes shouldn't appear/re-appear for a long time even at prime spots. But it's difficult to find that out before the fault gets dangerous.

    Back to the topic of measuring close passes: in the data from Dr Walker's study the distances to the passing vehicle was given to mm precision, but the distances out from the kerb were to 0.25m. I would guess that this distance out from the kerb would be more variable and better measurements of that might help show if there was a relationship between taking primary/being assertive/riding in the gutter and close passing. Another suggested relationship was that drivers might give more space to cyclists that they though might wobble, so measuring how wobbly the cyclists line was might give a useful comparison to passing distance. The width of road available to the passing vehicle (either to other traffic or to lane markings) must surely affect drivers deciding to make a close pass (or wait until a safe overtake is possible). And how long the wait is for a safe overtake would probably influence whether the driver is likely to take a chance on passing with less than desirable space.

    Posted 7 years ago #
  14. Beano
    Member

    Worth also looking at his more recent work, reported on here:

    http://www.bath.ac.uk/news/2013/11/26/overtaking-cyclists/

    Robert

    Interesting article; thanks @Roibeard. I was actually thinking "I wonder if i'll get more room if I wear an 'i'm filming' hi-viz top on my commute" as i cycled home last night. it appears not!

    Posted 7 years ago #
  15. wangi
    Member

    https://www.thestar.com/news/gta/2016/10/18/cyclist-says-his-pool-noodle-makes-toronto-streets-safer-for-him.html

    (I was initially baffled - i had read it as "pot noodle"... and the video hadn't loaded)

    Posted 5 years ago #
  16. neddie
    Member

    Drivers would see it as a target here.

    "Ho ho ho. See if you can hit the crazy yellow thing. For the LULZ."

    Posted 5 years ago #

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