By Gene VamCITIZEN STAFF WRITER ff \Bicycles are swarming over the University of Arizona this year, as students have taken to the pedals to avoid congestion on the car-clogged campus.The fad, which, according to some estimates includes about 1,500 UA students and faculty. members, has caught on also as a personal campaign against air-polluting cars and as a handy means of exercise.Pushing the trend toward bikes are both UA administrators and student leaders who want to see the twowheeled vehicles replace ears as student transporters.Local bicycle dealers are having a hard time keeping up with burgeoning demand. Russell and Sheperd Bicycles, located just south of the UA campus at 1007 E. 6th St., reports that it has a backlog of orders. The firm has sold about 300 bikes since sehool began early last month.The shoprs owner has just returned from Europe where he purchased 1,100 10-speed bikes, the most popular variety, to sell during the next year. The special trip was made because dock and trucking strikes, along with the huge demand, have made it risky to reply on wholesalers’' delivering an adquate supply.Prices range for the 10-speed from $65 to more than $300 for a specially-constructed bike made of aluminum.As more and more students and faculty members grab the handlebars and push the pedals, some UA officials foresee the day when 10,000 bikes may wheel down campus streets.While ear congestion lessens and bike-dodging increases at the UA, coeds report that pedal-pumping diminishes the posterior as well as the parking problem.