Getting across the Potomac may be a hassle during the week, but in this season there's another automobile challenge on the weekend - at least for those residents who make the trip to the beach and back. We noted the other day that during this year's Memorial Day weekend, there were some 40,000 more cars crossing the twin Bay bridges than on the same holiday weekend last year. Moreover, traffic has been increasing each year by 7 to 11 per cent.

Veterans of this trek are quick to note, however, that the Bay Bridge isn't always the biggest problem anymore. The whole ride is. There are those little bridges such as the one over the Choptank River; there's the drawbridge at Kent Narrows, subject to the whim of any passing sailboat; there are traffic lights that don't seem to help.

Just a staggering of work times in the city on Friday afternoons and Monday mornings might help ease the crush of the weekend rush hours on the Potomac, it might also have some value for the beachbound. Even now, many Shore commuters are finding that late-night or sunrise sorties are by far the best way to go. Otherwise, barring considerable expenditures to improve conditions for this seasonal trek, there's not much likelihood of great relief. While it may be of little comfort to anyone in that crawling cloud of exhaust this weekend, at least they're not in the weekly beach traffic in and out of Manhattan.