Is a fixed gear bike equipped with a "retarder"?
Bob Shanteau
521. A "retarder" is a device, other than a brake, which, when activated by the driver, applies a retarding force to the wheels of a vehicle without the use of friction. A retarder may be installed in or on the engine, exhaust system, drive train, or wheels of a motor vehicle, or an axle or wheels of a towed vehicle. A retarder may operate by altering the valve timing of the engine, by controlling the flow of a circulating fluid, by applying an electromagnetic force, by controlling the release of gases from the exhaust system, or by other means. A retarder may or may not be capable of stopping the vehicle upon which it is installed.Thus, the regenerative braking of a Prius is a retarder, as are the compression brakes (Jake Brakes) on a truck. Neither is technically a brake, however.
It occurred to me that pushing backwards on the pedals of a fixed gear bicycle is also technically a retarder, not a brake, since it slows the wheel without "the use of friction". This implies that a brake slows a wheel by the use of friction, which means a mechanical device such as a hand brake or coaster brake on a bicycle.
It's interesting that in its typically sloppy way, the CVC uses "motor vehicle" when it means "vehicle" and vice versa. In this case, it first says "retarding force to the wheels of a vehicle", then it says "A retarder may be installed ... on the ... wheels of a motor vehicle". Weird.
Bob Shanteau
Transportation Engineering Liaison
California Association of Bicycling Organizations
John Forester
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Dan Gutierrez
Bob wrote: “It's interesting that in its typically sloppy way, the CVC uses "motor vehicle" when it means "vehicle" and vice versa. In this case, it first says "retarding force to the wheels of a vehicle", then it says "A retarder may be installed ... on the ... wheels of a motor vehicle". Weird.”
.
Not weird at all. In the first instance, the general definition, that applies to all vehicles (though not necessarily devices like bicycles) is provided, then the law gives a specific set of instances (hence the use of the word “may”) that only apply to the motor vehicle subset of all vehicles which may have retarders.
What is more interesting to me is that there is a clear distinction between brakes (friction to slow a wheel) and retarders (slowing a wheel without friction), and that yes, backpressure from legs is clearly retarder operation, not a braking operation. Since the writers of the CVC saw fit to define a retarder as a piece of vehicle equipment, rather than equipment that applies to all street-legal conveyances.
Of course one can look at the definitions of other conveyance equipment to determine if this is a consistent or inconsistent pattern within the CVC. For examples:
108. "Airbrakes" means a brake system using compressed air either for actuating the service brakes at the wheels of the vehicle or as a source of power for controlling or applying service brakes which are actuated through hydraulic or other intermediate means
230. An "axle" is a structure or portion of a structure consisting of one or more shafts, spindles, or bearings in the same vertical transverse plane by means of which, in conjunction with wheels mounted on said shafts, spindles, or bearings, a portion of the weight of a vehicle and its load, if any, is continuously transmitted to the roadway when the vehicle is in motion.
605. "Tire traction devices" are devices or mechanisms having a composition and design capable of improving vehicle traction, braking, and cornering ability upon snow or ice-covered surfaces. Tire traction devices shall be constructed and assembled to provide sufficient structural integrity and to prevent accidental detachment from vehicles. …
Do notice that in all these examples, the term vehicle was used to describe braking components, axles, and tire traction devices, all of which may be on a trailer or on a motorized vehicle, so the term vehicle was used. For the case of a retarder, it is generally a piece of vehicle equipment, but can involve the motorized portion of a motor vehicle, hence the use of motor vehicle in the second sentence of that definition. In other words, the usage of vehicle and motor vehicle were deliberate and consistent.
Now to bicycles. It is clear that a bicycle wheel axle fits the functional portion of the CVC definition of an axle, except a bicycle is not a vehicle, so it can be construed in a strict construction of the code that a bicycle axle is not a CVC 230 “Axle”. Or one could interpret common equipment between vehicles and devices to fit the CVC definitions for vehicle equipment.
We can glean more about this issue by looking at the vehicle/device equipment codes:
26311. (a) Every motor vehicle shall be equipped with service brakes on all wheels, …
26454. (a) The service brakes of every motor vehicle or combination of vehicles shall be adequate to control the movement of and to stop and hold such vehicle or combination of vehicles under all conditions of loading on any grade on which it is operated.
(b) Every motor vehicle or combination of vehicles, at any time and under all conditions of loading, shall, upon application of the service brake, be capable of stopping from an initial speed of 20 miles per hour according to the
(1) Any passenger vehicle: 25 feet
(2) Any single motor vehicle with … of less than 10,000 lbs: 30 feet
…
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21201. (a) No person shall operate a bicycle on a roadway unless it is equipped with a brake which will enable the operator to make one braked wheel skid on dry, level, clean pavement.
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Unfortunately, the CA code writers did not use the term “service brake” to describe bicycle brakes, and allowed for a very low standard of braking performance (a rear wheel skid), with no grade stoppage, or stopping distance requirements at any speed. Because of this lack of specificity, it is not clear if “brake” in 21201 is the same as “service brake” in 26311/26454. Worse still, the “one braked wheel skid on dry, clean, level pavement” clause allows for very weak coaster brakes that can barely lock a wheel, and some are arguing that “braked” can include the retarding force of legs through the drivetrain as can be done on a fixie. This creates some legal gray space in California. For comparison purposes you may find it interesting to look at the equipment requirements of other relatively populous states to see how CA compares:
Pennsylvania (bicycle is vehicle):
§ 3507. … (c) Brakes.--Every pedalcycle shall be equipped with a braking system which will stop the pedalcycle in 15 feet from an initial speed of 15 miles per hour on a dry, level and clean pavement.
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Florida (bicycle is device):
§ 316.2065 … (14) Every bicycle shall be equipped with a brake or brakes which will enable its rider to stop the bicycle within 25 feet from a speed of 10 miles per hour on dry, level, clean pavement.
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Indiana (bicycle is vehicle):
§ IC 9-21-11-10 … Sec. 10. A bicycle must be equipped with a brake that will enable the person who operates the bicycle to make the braked wheels skid on dry, level, clean pavement.
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New York (bicycle is device):
§ 1236. … (c) Every bicycle shall be equipped with a brake which will enable the operator to make the braked wheels skid on dry, level, clean pavement.
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Oregon (bicycle is vehicle):
§815.280 … (2)(a) A bicycle must be equipped with a brake that enables the operator of the bicycle to stop the bicycle within 15 feet from a speed of 10 miles per hour on dry, level, clean pavement.
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Texas (bicycle is vehicle and device):
§551.104 (a) A person may not operate a bicycle unless the bicycle is equipped with a brake capable of making a braked wheel skid on dry, level, clean pavement.
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Not exactly clear or consistent, is it? What is interesting is that PA requires a bicycle with very good brakes that can stop the bicycle in 15 feet from 15mph; I doubt most coaster brakes could meet this requirement! In Florida on the other extreme, one could probably stop within 25 feet from a speed of 10 mph on a rickety beach cruiser that has rusting in the garage for 20 years!
Without clearer laws, the debates about the street legality of brake-less fixies will likely continue, though from a best practices/teaching perspective, it is pretty clear that legs are retarders, not brakes, and that it is relatively easy to add a front brake to most fixies to make them clearly street legal.
- Dan Gutierrez -
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