These are Federal regulations that put control of monitoring the safety of electric bicycles into the hands of the Consumer Products Safety Commission (CPSC), which supersede any state law that is more stringent, but only regarding safety equipment required on electric bicycles and not regarding whether electric bicycles are street legal. The states still decide what vehicles are allowed to use the roads in their state.
U.S. Department of Energy reports that “Since [1998, when federal rules
regulating equipment on these vehicles became effective], 37 states
have passed legislation allowing these vehicles to be driven on roads
with posted speed limits of 35 miles per hour or lower.” 
TEA-21 and SAFETEA-LU Specify that legal Ebikes, as defined above, are legal on urban bicycle trail systems getting any federal funding unless states or local entities have passed laws specifically dis-allowing electric assist bicycles. Under Federal Law, Ebikes are NOT considered motor vehicles unless the state or local entity has passed a law otherwise.
There is a MISCONCEPTION that when "motor vehicles" or "motorized vehicles" are disallowed by law or by signage, that this always means ebikes are illegal on trails. This is UNTRUE in many states; these terms do not include "legal low power electric assist bicycles", and can only be banned by passing a specific state or local law. (See TEA-21 Federal DOT Law)
SAFETEA-LU is a 2005 Federal Re-authorization of the 1990s TEA-21, and renews the exclusion of legal ebikes from the classification of 'motor vehicles' from urban trail use unless a specific local ebike statute is passed.
"Motorized vehicles are not permitted on trails and pedestrian walkways EXCEPT FOR: maintenance purposes, motorized wheelchairs, and—when State or local regulations permit—snowmobiles and electric bicycles. Electric bicycles are defined for the purposes of this Act as a bicycle or tricycle with a low-powered electric motor weighing less than 100 pounds with a top motor-powered speed not in excess of 20 miles per hour."
Safe, Accountable, Flexible, Efficient Transportation Equity Act: A
Legacy for Users, P.L.109-59 Available from the Government Printing
Office or online at www.dot.gov. Title 23,
There is some debate as to if and where the 100 lb rule applies. On the surface it appears to be valid on trails. Check your state and local laws for any recent changes.
As always, unsafe operation may be a specific illegal or civil matter to be handled by local courts.
new 2015 x treme clearwater beach cruiser electric bicycle black 300w sla, mongoose cx24v450 electric bicycle dirt bike motocross off road, 48v1000w26 front wheel electric bicycle motor kit e bike cycling hub conversion, 48v1000w 26 front wheel electric bicycle lcd display motor e bike conversion, ultra motor a2b electric bike , 2015 x treme x cursion folding electric bike replaces xb 310li lithium black, 36v 250w 26 front wheel electric bicycle light motor cycling hub conversion kit, x treme new xb 504 electric bicycle scooter moped 48v 500w rear hub power assist, iride 26 electric hybrid cruiser bike upto 18mph, 27 miles on one charge, 48v 1000 front wheel e bike conversion kit hub motor electric bicycle ebike, cyclamatic electric motor power plus bicycle mountain bike lithium battery black, new 2015 x treme x cursion folding electric bike replaces xb 310li lithium batt, prodeco phantom 36v 500w 9ah bike bicycle electric free shipping , 36v500w 26 rear wheel electric bicycle motor kit e bike cycling hub conversion, homcom 24 rear wheel 48v 1000w electric bicycle hub motor conversion kit lcd, x treme electric xb 210li electric bike 300w 16 wheels 15 mph folding lithium, lightning rods kit mid drive 2160 watts electric bicycle , xb 300li electric mountain bicycle by x treme e bikes, refurbished electric bicycle powered bike navigator electric bike on sale, 36v 250w 26 rear wheel electric bicycle light motor kit cycling hub conversion, damaged electric bike motor excalibur zeta iii a, new 2015 trail maker lithium electric mountain bike 300w 20 mph 26 wheels, x treme xb 305 sla e bike 300w womens electric mountain bike warranty, electric bicycle xb 300 sla extreme 20mph 300w black aluminium mens bike 26 inch, liberty electric folding bike 36 volt lithium ion bicycle fully assembled , cyclamatic electric motor power plus bicycle mountain bike lithium battery white, ezip e3 vibe electric bicycle with battery sla new in box, refurbished electric bike 24 inch power bike campus bicycle e bike blue on sale, jetson junior electric e bike cameo, schwinn tailwind electric mens bike large 700c not working battery, e bike front wheel 48v 500w ebike conversion kit electric bicycle hub motor new, new 2015 x treme trail climber lithium electric mountain bike replaces xb 305li, prodecotech storm 300 folding electric bicycle bike scooter ebike 36v 9ah 300w, schwinn tailwind electric mens bike medium 700c not working battery, ebike mountain bicycle electric scooter unicycle conversion e bike white 26 in, 26â€ť 48v 1000w electric bicycle cycle e bike conversion kit hub motor geared, 1, 920 watt electric bicycle conversion kit e bike crystalyte phoenix cruiser, schwinn transit electric mens bike 700ccharcoal, aowa electric bicycle very inexpensive transportation ecology friendly, electric bicycle for women ezip trailz, ebike mountain bicycle electric bicycle scooter electric unicycle conversion 26, x treme newport beach cruiser 2015 new electric bike 20mph pwr asst lithium, schwinn continental electric mens bike 700c 2007, ies electric foldable bike as is electric part needs to be fixed, tp 350 watt mens bike electric mountain bicycle shimano 7 gears electric bike, xb 305li step through electric mountain bicycle by x treme e bikes, 7 speed diac brake, 48v 1000w rear wheel electric bike conversion kits motor, easy motion electric bike pedal assist or throttle, only 275 miles, electric bike nylon battery case new, e bike evg ev global electric bike builders frame, lee iacocca, no reserve, x treme x cursion folding electric bike 2015 replaces xb 310li lithium red, new white 20 inch folding foldable electric bike bicycle lithium battery 24v9ah, electric bike fat tire conversion kit 1000 watt free shipping $44900, 48v 500w rear wheel e bike motor hub electric bicycle ebike conversion kit, currie izip trailz electric bicycle, brand new faraday electric bike sealed never opened, electric bike custom mens 15 speed 20 mph miles battery bicycle urban commuter, currie electro drive battery holder electric bike 24 volts , prodeco v3 phantom x2 electric bike appears brand new missing charger, new diy 30 mph electric bike ebike 48v 1000w with battery and charger, e bike mountain bicycle electric scooter unicycle red 20 in, 36v 800w brushless hub motor front wheel electric bicycle conversion outdoor gym, electric bike yukon trail ebike electric bicycle ms eb, e bike evg ev global electric e ride compact for parts must read, ebike 36v 500w 26in front wheel electric bike bicycle motor conversion kit usa, big cat e bykes mens electric fat cat all terrain mountain bike, mongoose 30 mph electric bike ebike 48v 1000w with battery amp charger, new pedego 36 volt 10ah black commuter cruiser electric bike battery, refurbished electric bicycle navigator sm24 power bike single speed, schwinn transit electric womens bike 700cwhite, no reserve pantera foldable electric bike 55km h 80 120 km range real bike look, heh massif electric fat tire bike ebike electric bicycle e bike, rayos 8 speed full suspension electric bicycle, 600 watts, electric bike conversion kit li ion 52 ah included 24v 250w 700c front wheel, new diy 30 mph electric bike ebike 48v 1000w with battery amp charger, 36v 700w rear wheel hub motor electric bicycle ebike conversion kit e bike, electric bike conversion kit li ion 52 ah included 24v 250w 26 front wheel, refurbished electric bike 24 inch powered bike e bike blue on sale, x cursion folding electric mountain bike by x treme, new 8fun bafang mid drive 48v 750w 25a electric bike motor conversion kit bbs02 , e bike rear wheel 24v 500w ebike conversion kit motor hub electric bicycle new, razor mx350 dirt rocket electric motocross bike pink new in box, schwinn searcher e8 24 volt electric bicycle women xsmall battery not working, 2015 clearwater beach electric cruiser bicycle300w motorred , pioneer bike inc eko bike electric bike, electric bike izip e3 ultra pedal assist amp throtle 500 w, e bike rear wheel 48v 500w motor hub electric bicycle ebike conversion kit new, electric bicycle prodecotech stride 500 black cruiser e bike 36v 12ah 500w, 36v 250w electric bike kit, homcom 2848v1000w rear wheel electric battery bicycle motor conversion kit lcd, electric mountain bike 29 1000w 48v free shipping free battery $999 sale, ideation industrial charger for mipower electric bicycle sc1240a 45v l 36v 53a, new 2015 southbeach electric cruiser bicycle black sla battery 300w 1 speed ,