Designing modern roadways is challenging, but designing a modern roadway along an historic route with strict regulations is even more challenging.

Route 1A is an old corridor with origins dating back to the 1920s. Originally stretching from Maine to Florida, the route generally follows a path similar to that of historic Route 1. Since its beginnings as a local road that linked various communities, it has been improved over time to its current conditions. However, since the road was not originally utilized by motorized vehicles, rehabilitation using current design requirements such as minimum or maximum cross slopes, minimum lane widths, and maximum profile grades can be difficult to accommodate without causing a significant ripple effect on neighboring properties.

A Complex Project Layout

A modern-day stretch of Route 1A runs through the coastal city of Beverly, Massachusetts, located north of Boston. The southern portion of the corridor, while being a mostly wide and straight roadway in an urban area, suffered from a lack of visibility due to its history of being bordered by mill buildings and other old infrastructure. To accelerate the redevelopment of the corridor, the city selected us to design improvements to two miles of Route 1A and several intersecting roadways. Our improvements included complete reconstruction of the road and sidewalks to current Massachusetts Department of Transportation and Americans with Disabilities Act (ADA) standards and replacement of much of the existing drainage system. Features of the corridor included three historic properties that abutted the corridor and five signalized intersections which were to be upgraded. One of the intersections, known locally as “Gloucester Crossing” is comprised of a pair of opposing, offset T-intersections bisected by a grade rail crossing. The city requested that the design for this complex location include reorientation of one of the T-intersections along with the signal upgrade. The active commuter rail system sends 26 trains per day through the crossing, which added to the complexity of the design.

Present day Gloucester Crossing following construction.

To address this complex intersection, we conducted a detailed traffic study to redesign the crossing and the intersecting streets. Our team prepared a design that focused on safety, while keeping the legs of the intersection open to traffic. Detailed traffic phasing plans were developed and extensive coordination with the rail operator was required to coordinate the new traffic signal timings with the grade crossing signals.

Accounting for Cross Slopes

One of the more complicated challenges that needed to be addressed was a section of the corridor that ran along the side of a steep hill. The corridor in this area is heavily developed with multiple storefronts. As noted above, the corridor has been improved and expanded over time, which meant the existing road cross section did not have a constant cross slope and the abutting storefront elevations varied. We also found that existing sidewalk cross slopes in this area varied widely from flat to four percent or above, and existing driveway slopes varied even more.

Newly constructed bump-out along Route 1A.

Design requirements dictated that the road would have normal two percent cross slopes. Then, in order to match existing storefront grades and meet ADA requirements, we incorporated small adjustments to the curb heights and modified the sidewalk construction, where possible. This allowed us to synchronize with driveways, building fronts, and sidewalks, none of which met at the same point. Our team designed a road profile that aligned with a majority of the abutters, while limiting impacts to the side streets. We then incorporated some unique sidewalk designs to mitigate the remaining elements, including varying the curb reveal by as much as an inch to meet necessary elevations and incorporating a cobblestone strip to make up additional vertical differences, since the strip is not considered sidewalk subject to ADA sidewalk requirements.

Newly constructed streetscape along Route 1A.

We also coordinated with ongoing construction on several abutting properties during the design phase. This meant coordinating with those developers to verify their design matched ours or that we accommodated any new sidewalk or driveway needs of the proposed development.

As a team, we worked hand-and-glove with the city and the contractor to navigate and solve some of the complex and unforeseen problems that can arise on a daily basis in an historic corridor of this nature. In the end, it’s a very rewarding feeling when you drive down the completed corridor and view the transformative effects and functioning elements of the project.