The couch potatoes would take a hit in Mayor Rahm Emanuel's proposed 2014 budget, thanks to a 50 percent increase in the amusement tax applied to cable TV bills. Ald. Pat Dowell, 3rd, isn't one to spare the aerobically fit.

Her suggestion: Require the growing legions of bicyclists in the city to pay a $25 registration fee.

Dowell's proposal drew hoots from many directions, but we think she's on to something. Not just because the city could use the money — though really, those miles of protected bike lanes are costing an awful lot, so why not? — but because her proposal also calls for cyclists to take a class on safety and rules of the road.

This makes perfect sense. Motorists have to pass a test before they can drive. They also have to register their vehicles. Cyclists should do the same.

The number of Chicagoans who commute to work on bicycles is up by more than 214 percent since 2000, according to the Census Bureau's American Community Survey. That didn't happen by accident. Former Mayor Richard M. Daley was an avid cyclist who cultivated Chicago's image as a bike-friendly city. Mayor Rahm Emanuel campaigned on a pledge to build 25 miles of new bike lanes annually.

The city's ambitious Bike 2015 plan envisions a 500-mile bicycle network. The new Divvy bike-sharing program has been met with great enthusiasm by tourists and downtown workers alike. It would be an even better thing with helmets, but that's an editorial for another day.

More bikes mean fewer cars, less pollution and fitter citizens. We know in our hearts that this is a good thing. But it scares us to death.

Why? Because we drive — and occasionally bike — in the city. In the corridors shared by two- and four-wheeled commuters, the morning and afternoon rush hours are mayhem.

Last year, 1,675 crashes between bikes and vehicles were reported in the city. Every driver or biker has a near-miss story to share.

Chicago doesn't have the luxury of designing a bike-friendly street system from the ground up. The confusing mashup of bike lanes — some protected, some buffered, some shared — is what you get when you retrofit a heavily trafficked grid to accommodate thousands of cyclists. Some motorists have learned to detour around the busiest bike corridors to get to work and back. Maybe that's the point.

We're not suggesting the cars should own the road simply because they were here first, but we do think the cyclists joining those cars on the road ought to observe the same rules. It's confounding how many will argue point blank that no, they shouldn't.

In Denmark, they note, cyclists are allowed to ride both ways on one-way streets. This is not an appropriate maneuver in the Loop. In Idaho, bikes can legally treat a red light like a yield sign; pedaling through without stopping is known as "the Idaho Stop." It has no place on Milwaukee Avenue.

The whole point of traffic laws is to promote orderly, predictable, safe travel. Vehicles are less likely to crash if each is where it's supposed to be. We think Ald. Dowell's bicycle safety course, coupled with a little targeted enforcement, would help drive that point home.