The 275-mile Tour of America will be easy to watch Sunday afternoon along its route into Washington or on the final six laps around the Tidal Basin and along the Mall. But with 75 racers on 15 teams swarming past and a complicated timing system, it will be hard to tell who's actually ahead.

The overall fastest time will determine the winner of the three-day race. The winning team is the one whose top three riders have the fastest collective time.

Time bonuses are awarded to the top finishers in each day's race, or "stage," and additional time bonuses go to the first three finishers in each of six sprints held during the Tour.

The one-kilometer sprints or "premes" are mini races within the race. They're held at predesignated places, with Sunday's two sprints being held at Featherstone Plaza in Woodbridge, just before the racers leave Prince William County on U.S. 1, and on Constitution Avenue on the third of the final six laps around the Tidal Basin and Mall.

There are also individual time trials Saturday afternoon on a 9.3-mile course at Richmond National Battlefield Park, which in effect add a fourth stage to the race. They provide a chance for the fastest individual riders to counteract the weight given to team performance and support in the road race.

The Tour, like the famous multi-day stage races or tours in France, Spain and Italy, is basically a team race. Lower- ranked riders on a team -- called "domestiques" -- help the team's top riders by blocking or hindering the opposition. No blocking is allowed during the fast and dangerous sprints and finish.

A team's best sprinters usually are saved for breakaways, sprints and the finish, riding for much of the race in the air pockets behind teammates or anyone else they can get behind, since air resistance and wind are major drags. RACE ROUTE You can watch the race anywhere along the route, which will use two lanes of four-lane roads from Virginia Beach to Williamsburg on Friday, Williamsburg to Richmond Saturday (largely on U.S. 60), and Fredericksburg to Washington on Sunday (primarily on U.S. 1 and the George Washington Memorial Parkway). Racers will average 25 to 29 miles an hour. That means their arrival in towns along the way can be predicted within 10 to 15 minutes. 9See map for the estimated earliest time of arrival in various areas.0 The second and third stages, in Richmond and Washington, will end with fast "criterium" racing around a short circuit on city streets, which permits spectators to watch the racers pass many times. The best places to watch the final day of racing should be on the Mall, around the Tidal Basin or in the grandstands on Constitution Avenue in front of the finish line. Generally, the race route will be closed to traffic, at least in one direction, for 30 to 60 minutes until riders pass by, followed by a caravan of nearly a hundred cars, motorcycles and a helicopter carrying support crews, officials and journalists. Sunday, the George Washington Memorial Parkway from Mount Vernon to Alexandria will be closed to traffic from shortly before 1 till after 2, according to U.S. Park Police. From Alexandria, the Parkway's northbound lanes and Memorial Bridge will be closed from about 1:45 to 2:15. All roads around the Tidal Basin and along the Mall west of 14th Street will be closed from about 2 to 3 for the finish of the race. The National Park Service suggests that spectators come by bicycle or park on streets north of Constitution Avenue or in East Potomac Park (Hains Point), which will be accessible from the Southwest Freeway even during the race. All three days of the race will be televised in their entirety in Europe. The final half hour, which is expected to be from 2:30 to 3, will be shown live on U.S. network television (CBS, channel 9). PRIZES Of the $100,000 in prizes, $80,000 will be awarded to individual racers and $20,000 to teams whose top three racers have the best collective times and have accumulated the most "points." The complicated point, time and cash-bonus system, tallied by computer, rewards cyclists for doing well in each day's stage, in the six sprints and in the time trials. Of the individual prize money, $35,000 is awarded for the best overall times at the end of the three-day race, ranging from $7,000 for first place down to $140 for 41st through 50th places. Another $35,000 is divided among top riders in the stages, and $5,000 is awarded to time-trial winners. An additional $10,000 is awarded to racers who accumulate the most points overall. This acts as a kind of double bonus to the top-15 finishers in each stage, the top-10 finishers in the time trials and the top three in the sprints..