Town councilors have sent the designer of a proposed pedestrian bridge back to the drawing board in hopes of building it at a lower cost. The latest estimate for the bridge is $780,000, or about $150,000 more than the councilors hoped. It is the second time the councillors asked for a redesign. A previous estimate for the bridge came in at $1.18 million. If built, the glass-enclosed bridge would pass over Route 108 from Newmarket Mills to the parking lot near the town library. It is intended to make the downtown more friendly to pedestrians.