The opening of a new section of I-215 between 21st South and I-80 in October helped reduce traffic along some of Salt Lake's busiest routes that month, according to a Utah Department of Transportation official.

Just how much connecting the belt route with the east-west interstate eased traffic congestion is expected to be measured by a study currently under way, said Mark Musuris, engineer for UDOT's transportation planning division.That study, which will compare traffic patterns during the three months before the Oct. 7 opening of the newest portion of I-215 with those during the first three months it is in use, is expected to be completed early next year.

A just-released UDOT traffic bulletin for October shows a drop in the number of cars and trucks passing through traffic count checkpoints located throughout the Wasatch Front compared to the same month in 1987.

The decline in traffic passing at least four of those points is likely a direct result of extending the belt route, Musuris said. The points he identified are Redwood Road, 40th West and two sections of I-15.

For example, the checkpoint located on I-15 south of the 17th South overpass recorded 156,978 vehicles driving by in October 1987. But in October 1988, only 145,234 passed by, a drop of 0.2 percent.

While that might not seem like much of a drop, the fact that traffic is declining at all is good news to harried commuters, most of whom travel at least part of the way to and from work on I-15.

The October report showed declines on all categories of roads throughout the Wasatch Front for the first time this year, including interstates. However, the year-to-date statistics are still slightly above the first ten months of 1987.

Musuris said beyond the impact of the new stretch of I-215, he could not identify a reason for the decline beyond the possibility that the number of cars and trucks on the road may be stabilizing.

Rural roads, in categories ranging from interstates to so-called collector streets, are seeing more traffic than last year, according to the traffic bulletin.

The interstates in rural areas recorded an 8.3 percent increase in traffic in October over the same month in 1987, and an 8 percent year-to-date increase over the first ten months of last year.

"We had very good weather during the month of October. Weather has an impact on traffic," Musuris said. " When it's snowing or the weather's bad, you would think twice about going out."

He said the deer hunt also helps boost traffic in October.