It's shaping up to be a battle between the councils, and the prize is the Cambridge Common.

Cambridge's City Council is considering a bill that would impose a $50 fine on bikers who ride through the Common, where many Cambridge parents bring their small children to play and where many senior citizens enjoy the fresh air.

There are already "no-biking" signs around the Common, but there is currently no law on the books to back them up. The bill pending before the council would add teeth to the signs, effectively making the Common off-limits to bikers--including the many Harvard students (and Quad residents in particular) who cycle through the Common to and from the Yard.

In response, the Undergraduate Council sent a letter expressing its opposition to the bill to all nine members of the City Council. The U.C. letter argues that banning bike-riding in the Common would endanger bikers, who would have to face the significant hazards of cycling on Cambridge's congested and often-snowy streets.

Who's right?

Niether--both sides have equal merits. The City Council's plan to protect little kids--certainly a noble goal--would put big ones in danger. And the Undergraduate Council's letter ignores the risk of bike accidents in the Common.

One of the best things about the Common is its playground, a mecca for Cambridge's parents and their toddlers. The Common is also a favorite spot for the local over-70 crowd.

These people are the ones the City Council is rightly trying to protect by making biking through the Common illegal.

While there's no history of bikers running into small children in the Common, there have been, no doubt, many near misses (I myself have seen several). And the possibility of an accident always exists, especially given the high speeds of bikers and the high concentrations of both kids and cyclists in the Common.

In this light, it seems hard to justify opposition to a law that would protect kids--just for the sake of convenience of bikers who don't want to go a halfminute and a quarter-mile out of their way.

But that's not the whole story. One of the worst things about the Common's playground is that it's located right next to the path that cuts through the Common. This path provides the shortest route for Harvard bikers to commute from the Quad to the Yard.

Sure, the Common is more convenient for bikers--but it's also safer.

These legitimate concerns about safety are the cornerstone of the U.C.'s case against the biking ban in the David A. Aronberg-drafted letter to City Councillors. The Undergraduate Council letter notes that for bikers, the alternatives to the Common are Massachusetts Avenue or Garden Street, both of which are Jam-packed with notoriously crazy Cambridge drivers.

That's dangerous for bikers most of the year, but particularly in the winter, when roads are made more narrow by cleared snow.

The Undergraduate Council also argues that bikers prevented from cycling through the Common at night would face the doubly dangerous choice of battling traffic on dark streets or walking their bikes through the Common, making them easier targets for muggers.