In the ongoing, heated battle between bicyclists just trying to stay alive and motorists trying to shave a few minutes off their commutes, the motorists have gained an important ally: bicycle manufacturers and bicycling advocates.

The manufacturers are hoping electric bicycles will help them dramatically increase sales. And they’re working with some surprising partners to win electric bicyles access to the precious few areas where bicyclists now are free from motorized traffic: off-road routes such as the Capital Crescent Trail.

The head of nation’s largest organized campaign for creating paved off-road bike trails acknowledges he has sometimes taken his own motorized bike along the Capital Crescent Trail without being sure if it’s allowed. (It’s not.)

Who would benefit from allowing artificially powered bicycles on trails? The world already has innumerable modes and venues for motorized transit. Electric-bike advocates describe a desire to accommodate an aging and out-of-shape population that still wants to experience bike trails. “I don’t think having additional people trying to use alternative means of transportation is necessarily a bad thing,” said Alex Logemann, a policy analyst at the industry-funded PeopleForBikes advocacy group.

But advocates offer no data demonstrating the demand or explaining why there isn’t enough paved roadway where motorized vehicles already are legal.

“There are many challenges with motorized vehicles on a shared-use path,” said Christopher R. Cherry, an associate professor of civil and environmental engineering at the University of Tennessee at Knoxville. “Safety being first and foremost.”

An industry lobbyist, Larry Pizzi, offers an egalitarian vision where trails are no longer the exclusive domain of riders physically capable of pedaling a bike. “It sort of levels the playing field,” said Pizzi, president of e-bike maker Raleigh Electric and chairman of the e-bike committee of the Bicycle Product Suppliers Association.

It’s all being done, Pizzi insists, in a way that ensures that motorized bikes are tame companions to their pedal-powered counterparts. The legal language he has been prodding states to adopt defines three categories of motorized bike. The least powerful — “pedal-assist” models with a top speed of 20 mph — is the type that communities would be expected to allow on paved bike-pedestrian trails. But all three categories allow up to 750 watts of power — “a lot of power,” Pizzi acknowledged.

This region’s main bicyclist advocacy group, the Washington Area Bicyclist Association, supports allowing motorized bikes on the Capital Crescent Trail and other trails. The group thinks motorized bikes “are important to getting more people riding,” said its executive director, Gregory Billing.

But WABA has not asked its members in its annual opinion surveys whether they agree. He recommended a 2015 survey by the League of American Bicyclists — claiming that a majority of bicyclists support the use of motorized bikes on off-street paved trails — as “illuminating to the attitudes and opinions of” bike riders. That survey’s author, Ken McLeod, a legal specialist at the League of American Bicyclists, admitted his figures were not a reliable measure. The survey was merely a compilation of postings to the league’s social-media accounts, and a full quarter of the 700 participants said they already own motorized bicycles. The sample was “not likely to be objectively representative of bicyclists in general,” McLeod said.

Given the acquiescence of their own advocates, bicyclists may not even realize the potential changes awaiting them on the trails. Despite being the nation’s leading force for creating paved off-road bike trails, Maryland resident Keith E. Laughlin said he’s barely aware of the issue of allowing motorized travel on them. The D.C.-based Rails to Trails Conservancy, where Laughlin serves as president, has no formal position on the matter. Laughlin said the trails they support were always “intended to be used by non-motorized vehicles.”

Laughlin has an electric model among his bikes and is open to the industry’s argument that even a token amount of pedal assist is an important distinction when considering trail-use legalities. He said he typically uses his e-bike for commuting to work along main roads such as Wisconsin Avenue but has sometimes taken it on the Capital Crescent Trail.

The National Park Service does not allow motorized bikes on its trails, including the D.C. section of the Capital Crescent Trail and the Mount Vernon Trail in Alexandria. The usual fine would be $100, though Lt. Christopher Cunningham, commander of the U.S. Park Police unit responsible for the D.C. part of the Capital Crescent Trail, said he doesn’t know of any such ticket having been written.

On the Maryland side of the Capital Crescent Trail, motorized bikes became illegal just this summer, the result of a decision by the Maryland National Park and Planning Commission, which has jurisdiction over Prince George’s and Montgomery counties.

In Arlington, which allows motors on routes such as the Custis Trail, state law allows the use of electric-powered bikes capable of traveling up to 25 mph. Arlington’s bicycle and pedestrian planner, David Patton, initially said there is no speed limit, then later acknowledged there may be one. “I am not a lawyer,” he said, “but there appear to be several ambiguous points in the state law.”

The uncertainties persist as the Custis Trail proceeds west. Jeff Anderson, president of the Fairfax Alliance for Better Bicycling, said he, too, wasn’t sure of what was legal where. “It’s just not on the radar in Fairfax,” he said.

The stealthy legalization campaign for motorized vehicles on trails suggests deep disappointment awaits either the industry or bicyclists. That’s because even the industry isn’t sure how many people would actually buy a bicycle that costs several thousand dollars if they’re not permitted on bike trails. That, however, should remain a problem for the manufacturers and not become one for the trail users.