Tuesday, August 29, 2006

Speed Humps, 20mph Zones, & The Future

Many councils have ongoing policies which each year introduce new 20mph zones in to residential areas. From a cycling point of view: Who cares? & Do they work?

20mph zones are more enjoyable to cycle, for exactly the reasons of relative speed posted about here. Two and four wheeled traffic generally flow more harmoniously in these traffic calmed areas.

When first introduced to my local area, there was the occasional idiot car driver who was desperate to scream past my bike, earning a tank slapping "boof" as he scrapes something expensive on a speed hump...

But it seems most people become used to the safer speed, albeit by force and not choice. I guess it's a demonstration of selfish culture, that 20mph zones only work when enforced by the physical impracticalities posed by speed humps. Meh.


Up to 20mph on flat, is a speed accessible to most cyclists, perhaps not always if the wind direction is against them, but certainly if the wind is coming from behind them, giving some welcome assistance.

I find the short wheelbase of a bicycle means I can ride over speed humps effortlessly quicker than cars do. Whereas in my car I have to slow right down, or else risk damage to the undercarriage (as previous drivers have found out, judging by the wounded tarmac above).


The majority of residential roads are a minefield of potential hazards, often with dense rows of parked cars making visibility quite obscured. E.g. Who knows when a family cat might run out from underneath parked cars? Or when a car door may be unexpectedly swung open? Or when a football rolls in to the road, chased by a child? Or when cars reverse from driveways after an obscured bend?

In places like London, these crowded & populated urban & sub-urban settings are so widespread, that I feel many people become comfortable and nonchalant with the density, to the extent it is quite natural to drive through residential roads at excess speeds which don't acknowledge the ever-present residential hazards.


20mph zones, although employing rigorous physical deterrents, still often don't enforce the 20mph limit. When the speed humps are spaced too far apart, modern cars are easily hitting 30mph -40mph on the flat spaces between speed humps: Nullifying any calm and safe cycling evironment a 20mph zone may have set out to promote.

By spacing road humps closer together, traffic planners could make a 20mph zone genuinely successful - so that by the time a car (even a high performance car) accelerates to 20mph, it has to slow for the next imminent speed hump.


But is there any need for speed humps at all? Here's an idea:

Consider the technology already in use:

  • Cruise control - The car automatically maintains a constant chosen speed.
  • Electronic maximum speed limiters - Although a car can potentially go faster, manufacturers impose restricted maximum top speeds (e.g. 155mph).
  • GPS route navigation (e.g. Tom Tom / Garmin / Navman / etc ).

It is only a short hop of imagination to combine the existing technology to eliminate dangerous speeding in residential areas.

Given that each individual speed hump costs around £1,000, GPS nationwide could be a whole lot cheaper & smoother method of managing the speeding problem.

Consider that the GPS finds your route, and knows your location. As easy as it is to know about hotels in the area, the GPS device could similarly be programmed to know the speed limit of the present road. If the GPS could talk to the car's engine management system, the two would guarantee speed limits are not exceeded.

This idea would generate a double benefit of safer traffic speeds through neighbourhoods, and reassurance the driver will never be caught speeding and suffer the fines and penalty points which go with it.

Given satellite navigation has become much cheaper recently, and is even sold as standard on some cars, this whole idea could be easily distributed as people renew their cars. Even if only 1 in 10 cars benefited from GPS speed management, all the cars in traffic following behind, would also be affected, in an ad-hoc Pace Car kind of situation.


  • 20mph a better traffic speed to cycle amongst.

  • Bikes less affected than cars over speed humps.

  • 20mph is required because people become accustomed to speeding in residential areas.

  • Speed humps only effective when continually located close to the next one.

  • GPS speed management is a cheap & easy near-future solution.

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Sunday, August 27, 2006

Best Cycle Route In London?

One legacy of the infamous Millennium Dome on the Greenwich peninsula, is a quality stretch of National Cycle Route Number 1, which passes through it.

The cycle route around the dome really is the complete antithesis of bad cycle lanes. As shown in the pictures, the design is wide enough for overtaking, riding in pairs & talking, and allowing a safe gap between oncoming cyclists, (something many other cycle paths fail at).

The purpose built cycle route, alongside the river Thames, genuinely deserves some credit for the well-designed, fit for purpose, facility which is available today. It's fine to ride, with a smooth flat surface.

A cycle map for the Greenwich peninsula is available on TfL's London Cycle Guide 11. Links available on my previous post: London cycle route map resources.

This is how off-road cycle routes should be.

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Tuesday, August 22, 2006

Media Attack On Cyclists Justified

Cyclists are like badly behaved toddlers running around the ankles of shoppers, as adults navigate their trolleys around other trolleys in a supermarket.

The bicycle is a vehicle; riders share the road space with a variety of other vehicles. A gruesome recipe of flesh & metal is only avoided because of the compromise and co-operation that is set-out in the Highway Code.

To arrogantly disregard the code, cycle through red lights, harry pedestrians out the way as they try to cross on a green man, make entire journeys on the pavement "’cos it's safer for me" (instead of the road - where vehicles live), and other examples of untrained and inconsiderate cycling, really reveal to me that the recent media onslaught highlighting negative examples from cyclists, is pretty justified.

When surveys are reporting endemic errant cycling, such as 50% of cyclists red-light-jumping, which matches up with my daily experiences, it appears "the cyclist" - the stereotype, is literally goading everybody else, including the "authorities" (as limp and without authority as they are...), showing that cyclists can do what the hell they want, overtly ignore their responsibilities, and generally piss everyone else off who are trying to co-operate and follow the Highway Code.

What this shows, is that human nature left to its own choices opts for the selfish gains, often at the inconvenience of others.

Stealing time by not stopping at red lights, of course has benefits, in the same way stealing a cake from a shop has the advantage of not having to pay for it.

Not only highlighting the failings of cyclists, this current situation I am witnessing, highlights the failure of enforcement. Such widespread and frequent law breaking is so easily available to any cyclist who wishes to make that choice, because there is no deterrent or enforcement of the alternative.

Contrast with the driver who is coerced in to compliance by speed cameras, red-light-jumping cameras, bus lane cameras, parking cameras & wardens, in an Orwellian but effective, big brother style of constant enforcement. It seems cyclists need the same?

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Monday, August 21, 2006

Surrey Quays This Thursday

Just a quick plug for anyone who knows some fresh cyclists looking for some inspiration / assistance / riding tuition in and around the SE16 area of London.

It's an event on Thursday 24th August (11am - 7pm) called "Bike Magic Day" at Surrey Quays.
Offering stunt shows, simple local bike rides, and help with basic maintenance issues.

Perhaps the most attractive offer, for anyone considering beginning riding / cycle commuting, is an offer from "Cycle Training UK" of seriously discounted cycle coaching.




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Wednesday, August 09, 2006

Enjoying The Non-School-Run

The biggest development was when the schools broke up for summer. Immediately, I noticed traffic jams shorten, and traffic flow reduce.

I recall reading various reports which assert the dreaded school run, is to blame for something like 33% to 50% of rush hour traffic. On my ride, it's VERY noticeable, especially during the morning journey.

This bliss of quieter roads & less cars, has got even better in August, which I guess is down to the typical holiday season. Whereby all the little kids are now getting driven around the streets of tourist resorts, instead of to school. The obese little sods!

This status quo lasts from July to September, and I'm going to enjoy it to the max.

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Sunday, August 06, 2006

Speed, Speeding, or Relative Speed? Huh?!

While motorists are constantly under threat of being caught speeding, this cyclist is interested in a different kind of speed.

The Theory

Let's say a car turns a bend and gets first look at a cyclist in front, who is 50 meters down the road.

If the car is travelling at 30mph, and the bike is stationary (0 mph). The car will be where the bike is, in 3.728 seconds.

If the car is travelling at 30mph, and the bike is travelling at 10 mph. The car will be where the bike is, in 5.592 seconds.

If the car is travelling at 30mph, and the bike is travelling at 25 mph. The car will be where the bike is, in 22.369 seconds.

This example makes it patently clear that the faster the cyclist's speed, the longer the car behind has; to spot the cyclist, consider the best way to overtake, to plan and execute this manoeuvre.

With the '30mph car' vs '25mph bike' example, the ample time gap (22 secs before overtake) is present, because the car is only catching the bike at a rate of (30mph - 25mph = ) 5mph.
This is the relative speed between both vehicles.


Should the car be breaking the 30mph speed limit, let's say 45 mph (which is 198 feet per second!), and the bike is going uphill at 10mph, the car will be on top of the bike in 3.196 seconds.

That is quicker than if the bike was even stationary, and the car was doing 30mph!
(Relative speed in these examples:
e.g.1: 45mph - 10mph = 35mph.
e.g. 2: 30mph - 0mph = 30mph)

There is no doubt modern cars have fantastic technology, and in dry theoretical conditions can brake very efficiently once the pedal is applied. However, the weakest link as ever, is the human decision maker at the helm.

3 seconds sounds ok while sitting at a PC reading this, but tasks like mirror checking, indicating, changing gear, turning, checking speed, turning, etc, all take valuable seconds.

The more closely matched a bike and car's speeds are (i.e. a low relative speed), the more time the driver has to carry out the right checks and tasks, to overtake the cyclist safely. Cars being driven at excess speed have the opposite effect, so is more dangerous.

It is worth mentioning of course that managing relative speed (between bicycle and car) is largely the responsibility of the motorised vehicle, because it is much easier to control speed up or down - via engine power, than it is via pedal power.

The Faster The Better

Perfection sometimes, is when relative speed = 0 mph. I feel very safe bombing down hill at 25mph in the middle of a lane, at a similar speed to surrounding traffic. Because I just become another vehicle, in line. Well away from parked car door-zones, and in easy view of other drivers.

A small fan-club might form behind, of drivers who aren't able to overtake me, but they're not at all bothered, because we're all making fair progress.

Of course there are many other circumstances, which will require a different approach, and a relevant speed. (E.g. Filtering slowly past traffic queues / Densely populated pedestrian areas / etc).

Situations like heavy traffic might look daunting to some, but if the traffic is only ambling along at 10-15mph or so, this makes it a lot easier for me on a bicycle join in at 15mph also, to achieve that relative speed of zero.

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Thursday, August 03, 2006

Hmmmm :-\

So I left it until I woke up this morning, to decide whether to commute by bicycle / car / train today. Not the best time for decisions for me, as I barely have enough cohesive brainpower some mornings, to put milk & cereal together!

In my corner of London, the sky looked grey. Plump with moisture ready to drop, swaggering in the same way we school-kids used to wield bouncy water bombs.

Potentials, and what ifs aside, factually; it was dry, bit windy, but very cyclable either way.

I seemed to have a love / hate special connection with the weather today. As in;

The weather loves to hate me.

Because exactly as I donned my cycling shorts, literally the act of pulling them up, was a slow-motion surreal coincidence, signalling for the rain to start falling down. Bastad!!!!

Probably because I've got so used to the constant dry heatwave we experienced, I began my ride trying to counter-attack the rain with a deluge of expletives, and make it go away.

It didn't work.

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