The Massachusetts Department of Transportation should be applauded for its efforts to finally get the Longfellow Bridge closer to completion, in spite of delays in the schedule (“Longfellow costs? A bridge to be crossed,’’ Metro, Aug. 18). This project had been languishing for more than three decades for lack of funding.

Two points need to be made here. First, it is difficult, if not impossible, to accurately estimate the cost of rebuilding a historic structure such as this magnificent bridge, as compared with building a totally new structure with a new design. There are so many unknowns in a project of this complexity, including the public’s expectations and the mitigation necessary to minimize construction impacts. Second, the public must understand that delaying infrastructure projects only results in escalation of cost and corresponding endangerment of public safety.

The estimate to rehabilitate this bridge during my tenure with the Metropolitan District Commission stood around $40 million, and that was in 1995. So we shouldn’t be surprised if the cost for the current project goes over $300 million. That’s the price we pay for delaying fixing our infrastructure, whether in Massachusetts or around the country.

We should welcome the news that finally the state will be getting this historic bridge completed in 2018 — a bridge that is like the jewel in the crown in our park system.

M. Ilyas Bhatti, Canton

The writer, who was MDC commissioner from 1989 to 1995, is an associate professor of construction management at Wentworth Institute of Technology.