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Jim Chisholm

@chisholm4trail.bsky.social
68 followers 136 following 37 posts

Campaigner for Sustainable Transport for 25+yrs. Researcher? at then TRRL '69-85. Volunteer restorer of Canals in 1970s. Chisholm Trail a half done job! Started cycling 50+ yrs ago due to ill health.

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Jim Chisholm @chisholm4trail.bsky.social · 01/09/2026
In mid 70s @ TRRL worked good friend, 2 plan experiment 2 try & determine 'perceived cost of interchange' No bluesky money! He has sadly died, & I've 2 plan a trip to Lakes. I route with 2 rail changes at cost of 2 hrs time. 1 involves 0 min bus/rail (60min wait?)interchange. A boat trip looks good
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Jim Chisholm @chisholm4trail.bsky.social · 13/08/2026
This makes excellent reading, as does full report: victimscommissioner.org.uk/document/for... 18yrs ago, whilst cycling, I was hit from behind. Apparently my fault for being there! Driver not charged. Took much time for police to admit errors. A year later wrote: www.camcycle.org.uk/magazine/new...
victimscommissioner.org.uk
Forgotten victims: Barriers to justice following a road traffic collision - Victims Commissioner
Despite an estimated 29,896 people being killed or seriously injured on roads in England and Wales in the year ending
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Reposted by Jim Chisholm
Tom Flood @tomflood.bsky.social · 10/08/2026
free range.
two cars driving with two chickens below
"Feel bad for the kids in those cages, they really should be free range"
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Jim Chisholm @chisholm4trail.bsky.social · 09/08/2026
Shelford 2 York on weekday morning: National Rail, LNER, & EMR give diff times, & diff changes, with none suggesting changing at Cambridge South, & only EMR allowing via Ely. Looks like Cross Country arrives P'bro at same min, of hr that York departs! When young & cross platform it could be done!
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Reposted by Jim Chisholm
road.cc @roadcc.bsky.social · 05/08/2026
“As all people using these roads are still being exposed to illegal levels of pollution, why is it that only people walking and cycling are prevented from using the road?”
road.cc
“It’s perverse”: National Highways closing cycle paths – because the roads beside them are too heavily polluted
National Highways has been accused of “perversely penalising” cyclists and pedestrians after it was revealed that a number of shared-use paths have been closed due to heavy pollution on adjacent roads...
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Jim Chisholm @chisholm4trail.bsky.social · 16/07/2026
A better 'metric' might be the no. of drivers who also regularly cycle rather than % who cycle? There will be a correlation between the two metrics, but I suggest mine may be the causal one. Also important is how many more walk or cycle following the change, especially if alternative was to drive.
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Reposted by Jim Chisholm
Martin Rathfelder @rathfelder.bsky.social · 12/07/2026
What is Reform's policy on sycomore trees? Dangerous immigrants propagating themselves all over the place!
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Jim Chisholm @chisholm4trail.bsky.social · 12/07/2026
Many benefits could be had by having more stoppers . Extend N'umberand line to Morpeth). More fasts could pass more stoppers with loops at Alnmouth & Berwick & Dunbar. It is lack of Amps that restricts capacity for Electric trains. Four Track is OTT. Needs better frequency of trains to beat cars
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Jim Chisholm @chisholm4trail.bsky.social · 03/07/2026
Should we expect Cambridgeshire Constabulary to enforce such limits, as is done by most forces most forces?
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Jim Chisholm @chisholm4trail.bsky.social · 03/07/2026
Never even knew the street name, but it was probably a little later, but in same area of Norwich. Searching TRRL archive is terrible, and tried asking Norwich Civil Soc if they knew of report. Wouldn't want to think those days in darkened room were wasted..Would have been easier if video and colour
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Jim Chisholm @chisholm4trail.bsky.social · 03/07/2026
In '70/71 at TRRL as 'lowest of low'.., I spent hrs in a dark room analysing time lapse film of peds. in a small Norwich St before/after cars excluded (1st in UK?) Clear that then more peds crossed street & more visited shops. 35yrs later tried to find research report & failed..Learning from History
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Jim Chisholm @chisholm4trail.bsky.social · 02/07/2026
Given that 'inertia' causes most damage/injuries in crashes, and weight most road damage, Why not multiply the weight of a car (in tons) by maximum speed (kph) to give a quotient for Vehicle Excise Duty (Road Tax) for a year? Too low? Inertia is weight x speed squared! Would that be too high?
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Jim Chisholm @chisholm4trail.bsky.social · 01/07/2026
Isn't this nearly as bad? Part of R&L over 30mph on NCN11 with 1k cycles per day 1.8m fences & blind corners. Shared use 'actual' 3m (effective 2) single lane under 3.9, which most on cycles will use. LT North crosses Dutch Kerb! at acute angle. II'ee crossing 1.2m? All ATE 'approved'?
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Jim Chisholm @chisholm4trail.bsky.social · 29/06/2026
We've some of those in Cambridge, but not in as many places as there should be! Not sure if they discriminate against carbon fibre frames as they are loop detector driven
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Reposted by Jim Chisholm
Solve the School Run @solveschoolrun.bsky.social · 26/06/2026
"Car manufacturers have spent decades pushing large expensive cars at the expense of smaller models. After 25 years of relentless growth, our streets are dominated by oversized SUVs that cities simply weren’t designed for." Anna Krajinska of @transportenvironment.org
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Jim Chisholm @chisholm4trail.bsky.social · 24/06/2026
London’s ULEZ and T-charge linked to reductions in emergency hospital admissions. Need similar controls in all Urban Areas www.imperial.ac.uk/news/article... 8.1 % reductions in yearly trends for cardiovascular disease, 6.2% for respiratory disease and 3.1% for all cause related hospital admissions
imperial.ac.uk
London’s ULEZ and T-charge linked to reductions in emergency hospital admissions
New analysis from Imperial researchers has found that measures to cut air pollution from vehicles in central London are associated with a fall in hos...
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Jim Chisholm @chisholm4trail.bsky.social · 23/06/2026
I like this, and post: www.youtube.com/watch?v=JK0V... Although sometimes difficult, I try not to use words 'cyclist' & 'motorist' as it tends to imply 'mutually exclusive sets'. I drive & I ride a bike It was @rafe-s.bsky.social s.bsky.social decades ago suggested that. It can soften any division.
youtube.com
Why London Drivers Hate Cyclists (And Why They’re Wrong)
YouTube video by Human Human Stories
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Jim Chisholm @chisholm4trail.bsky.social · 22/06/2026
Clarence shot a film in Cambridge 10+years ago. Some of the LTNs there had already existed for 30 years. He filmed a 92 year old cycling thro one set of bollards but STOPPED filming just seconds before he turns and shouts 'I'm 92'. (@4.22) see: www.youtube.com/watch?v=9-p3...
youtube.com
Cambridge: Britain's Cycling Capital
YouTube video by Streetfilms®
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Jim Chisholm @chisholm4trail.bsky.social · 21/06/2026
There was a development ('big pharma'?) in Kent where all those who didn't use the car park got a benefit (Was 10min extra flexi-time?) So if you walked, took bus, or didn't drive you got benefit. ould do that for ALL those at NHS facilites, even if benefit were just a sandwich... Big pharma closed.
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Jim Chisholm @chisholm4trail.bsky.social · 20/06/2026
Ironically, it was 'standardi'z'ation of US and following UK/EU bumper heights that lead to increased ped injuries. Bumpers then at adult knee height & more risk of 'child' under! see: www.trl.co.uk/publications... There is I believe some earlier TRRL work, but can't find it
trl.co.uk
TRL | The trajectories of pedestrian dummies struck by cars of conventional and modified frontal designs
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Jim Chisholm @chisholm4trail.bsky.social · 19/06/2026
Had a friend, 80, who had cycled almost daily. In Cambridge, a pedestrian stepped off the kerb, directly in front of him at lights (GREEN for bikes but RED against peds). He broke his wrist badly & never cycled again. Apparently she thought she'd done nothing wrong. Sequence at lights was confusing.
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Jim Chisholm @chisholm4trail.bsky.social · 18/06/2026
@pactsuk.bsky.social When I posted this I didn't make it clear that Cambridgeshire Constabulary has over the whole of Cambridgeshire issued zero NIPs for exceeding 20 limits in whole of 2024 @rafe-s.bsky.social @emilykerr36.bsky.social LA proposing speed humps on busy cycle routes as alternative!
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Jim Chisholm @chisholm4trail.bsky.social · 18/06/2026
@rafe-s.bsky.social @emilykerr36.bsky.social @emilykerr36.bsky.social @pippaheylings.bsky.social 20mph streets (1k bikes p/d) my Cambridgeshire village have an 85%of 30.5. Police say (via MP)"I can confirm that as a rule we do not enforce 20limits @20splenty.bsky.social say zero NIPS in '24. Help!
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Jim Chisholm @chisholm4trail.bsky.social · 15/06/2026
@lauralaker.bsky.social On a more serious note... AND I wrote about poor and dangerous infrastructure 25 years ago see: www.camcycle.org.uk/magazine/new...
camcycle.org.uk
Flush out dropped kerbs
Whilst living near Reading I knew of someone who had an accident cycling to work due to a poorly designed cycle facility, specifically a dropped kerb. He later sued the local council. I mentioned the ...
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Jim Chisholm @chisholm4trail.bsky.social · 13/06/2026
@walkwheelcyclet.bsky.social Can't @ategov.bsky.social Stop daft works on existing NCN route? 1k cycle trips per/day do R then L. Narrow shared use (30mph rd, 1.6m fence + blind corners). Most will use on road with 'critical width' lane + not flush, not 90deg crossing of inappropriate Dutch Kerb!
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Reposted by Jim Chisholm
Martin Rathfelder @rathfelder.bsky.social · 13/06/2026
The nuclear enterprise already consumes roughly a fifth of the defence budget — £12bn out of £60bn last year. Never been used. Why do we want to be a nuclear power? To defend our Empire? www.ft.com/content/c5af...
ft.com
The strategic dilemmas behind Britain’s defence spending mess
At the heart of the debate is not just how much the UK should spend on the military, but what types of threat it faces — and ultimately, its place in the world
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Jim Chisholm @chisholm4trail.bsky.social · 13/06/2026
Fourth power rule? Has been known for 50+yrs? My first Mini had axle wt of c 250kg. A typical EV SUV will be over 4x that, so damage factor will be more than 250 (old) Minis! Those weak town streets/rural lanes with few HGVs are now battered by bloated 'cars'! en.wikipedia.org/wiki/Fourth_...
en.wikipedia.org
Fourth power law - Wikipedia
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Reposted by Jim Chisholm
Tom Flood @tomflood.bsky.social · 11/06/2026
Not complicated
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Jim Chisholm @chisholm4trail.bsky.social · 06/06/2026
@oldtrotter.bsky.social So when an LA introduces speed humps 4.5m wide (with narrow gutters) on a two way road who gives way and should motors attempt an overtake?
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Jim Chisholm @chisholm4trail.bsky.social · 05/06/2026
It is the utter reliability of cycling that makes it quicker than driving. I can stay in bed longer if cycling the 5 miles to Cambridge station for a fast peak hour train to London than if I drove.
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Jim Chisholm @chisholm4trail.bsky.social · 05/06/2026
A dropped kerb can be dangerous for cycling if natural line is far off from a right angle. Flush kerbs needed. See DfT LTN1/20 Cycle Infrastucture Design (section 9.3.5) and also this from me, 25 years ago! www.camcycle.org.uk/magazine/new...
camcycle.org.uk
Flush out dropped kerbs
Whilst living near Reading I knew of someone who had an accident cycling to work due to a poorly designed cycle facility, specifically a dropped kerb. He later sued the local council. I mentioned the ...
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Jim Chisholm @chisholm4trail.bsky.social · 04/06/2026
At CBC, consultant (cycling) late for my appointment! Saw my cycle bag, & asked 'Where did you park?' After40 yrs, I know hidden spots. His spot fenced off 4 works! Yet they are building more MSCPs, despite an 'on-site' Cambridge South railway station opens in days! CBC Needs 100s more cycle spaces.
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Jim Chisholm @chisholm4trail.bsky.social · 01/06/2026
Two yrs ago, I drove from Ely late one night. Was amazed at the inconsistency of signing, lining, lighting & speed limits. Looked at crash stats & saw lots of injuries to vulnerable road users. Spend relatively small ££s on safety improvements. More capacity on rail better than more capacity on road
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Jim Chisholm @chisholm4trail.bsky.social · 31/05/2026
Have you got 'The Road Makers'? Not a sight of 'hard hats' or 'high vis'!
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Reposted by Jim Chisholm
TallBikeGuy @thetallbikeguy.bsky.social · 29/05/2026
Great graph from Russell King via #BikeIsBest
A graph that shows the circular actions of widening roads, building free parking and designing roads for driver comfort all result in increrased congestion and roads becoming less safe.
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Jim Chisholm @chisholm4trail.bsky.social · 26/02/2026
@andy-cox.bsky.social Is limit+50% defined as 'excessive' & if 15% are over limit+50% is it reasonable to expect some police enforcement, even if only a 20mph limit? Source of info in public domain? I don't want to wait until Road Safety Strategy, & updates to 15yr old 'setting local speed limits'
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Jim Chisholm @chisholm4trail.bsky.social · 24/02/2026
@walkwheelcyclet.bsky.social I'm very disappointed as I emailed the trust week ago about serious issues with proposed changes on NCN 11. I've followed it with a call. No response. Isn't the proposed use of Dutch Kerbs not only inappropriate but dangerous? Bearing left at 12mph risks a serious fall!
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Jim Chisholm @chisholm4trail.bsky.social · 23/02/2026
Do I assume that is a 'shared use' footway, so cycles don't turn across a 20mm lip? Wrote 'Flush out Dropped Kerbs' in 2000: www.camcycle.org.uk/magazine/new... but in my village Dutch Kerbs are proposed across side street with NO footway & where crossed obliquely
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Jim Chisholm @chisholm4trail.bsky.social · 16/02/2026
Anyone seen the use of Dutch Kerbs across a side road where there is NO footway, or one on a long curve, where a side road bears off meaning you approach the kerb at 15deg. I could show you such a proposal. They and speed humps are about to be approved, and on the NCN
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Jim Chisholm @chisholm4trail.bsky.social · 08/02/2026
Cheers. I've seen no formal Guidance on use of Dutch Kerbs, and use mainly post-dates LTN 1/20. I wrote this 25 years ago: www.camcycle.org.uk/magazine/new... {Flush out dropped kerbs}
camcycle.org.uk
Flush out dropped kerbs
Whilst living near Reading I knew of someone who had an accident cycling to work due to a poorly designed cycle facility, specifically a dropped kerb. He later sued the local council. I mentioned the ...
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Jim Chisholm @chisholm4trail.bsky.social · 07/02/2026
@rantyhighwayman.bsky.social Asking4Friend... Is this a safe/appropriate use of Dutch Kerbs (in purple). Bearing left on a falling gradient into Magog Way. Surely such kerbs should be crossed at near 90deg? Wouldn't it fail a Safety Audit...
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Jim Chisholm @chisholm4trail.bsky.social · 23/01/2026
@londoncycling.bsky.social Ask4friend... Is it good use of ££££ to put Dutch kerb & raised footway across entrance of side road with NO footway, or shared -use path on either side for over 50m? on minor road. Footway only on opp side. Is it even safe with wide bellmouth (cycles enter on skew not 90)
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Jim Chisholm @chisholm4trail.bsky.social · 20/01/2026
Lot in common with Water & Transport. Those with no meters have no incentive to reduce use, so others pay more than fare share. For motors, those without cars still pay for roads, & those driving excessive miles in heavy vehicles (4th power rule) trash & congest roads, so less safe for others
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Jim Chisholm @chisholm4trail.bsky.social · 03/10/2025
Used that road, say weekly,over 10 yrs. I wouldn't start from here. If ALL free parking removed 20 yrs ago most of problems, except priority at end would have gone. Most cars are just hunting for free spaces. Reducing free commuter parking on the fringes, reduces the amount of motor traffic in city
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