The construction for I-81 began in the late 1950′s, after the Federal-Aid Highway Act of 1956. The elevated portion of the highway through downtown was completed in the 1960′s after the then current Mayor and city engineer worked with the state to shift it three blocks eastward.

The Tech Memo found that highways within the primary study area generally have sufficient capacity for current traffic volumes, meaning they are operating at LOS A, B or C during morning and evening rush hours. Certain areas along I-690 and I-81 in the downtown area approach or exceed capacity (LOS D/E/F) during peak periods. A number of merge/diverge areas and on/off-ramps are also operating at LOS F. The average speed in these congested areas are »

In transportation planning, we often talk about Level of Service or LOS for short. But what exactly does it mean? Level of Service is an indicator of congestion on road segments and at intersections. We use LOS to measure the delay experienced by drivers on a scale of A (short wait times or low volumes of vehicles moving at free flow speeds) to F (long delays or high volumes of vehicles with slow travel speeds).

Collision data were obtained from NYSDOT for the most recent three-year period available (February 1, 2006 – January 31, 2009) to calculate accident rates for the I-81 and I-690 corridors and their on- and off-ramps. These accident rates were then compared to the statewide average accident rates for similar types of roadways. The highways in the primary study area have a relatively high rate of accidents when compared to statewide averages. This »

NYSDOT’s draft Technical Memorandum #1: Physical Conditions Analysis (Tech Memo #1) found that between 2002 and 2008, employment in the City of Syracuse dropped by approximately 11,000 jobs while employment in Onondaga County increased by almost 7,000 jobs.

So what exactly is a viaduct? A viaduct is a continuously elevated bridge structure. When we reference the I-81 viaduct, what do we mean? The viaduct section of I-81 is a 4,097 foot long bridge composed of 124 individual bridge spans.  The viaduct stretches from approximately Van Buren Street (or the Carrier Dome) to Willow Street.

Pavement and bridge conditions are determined by periodic inspections conducted by NYSDOT. A NYSDOT surface rating survey completed in 2008 found the majority of the pavement in the [primary study area] to be in “good” condition. However, given their age, the majority of highways in the primary study area will need either major rehabilitation or reconstruction by 2040--the design year for any major highway project that may result from The I-81 »

Before delving into details on traffic volumes and bridge conditions, it’s helpful to understand how I-81 fits into and affects development patterns in the region. Existing land use in Onondaga County generally follows a traditional radial pattern. The urbanized area is centered in the City of Syracuse, where many of the region’s jobs and about 30% of the population are located. This urbanized area has expanded over time to include first- and »

This is the second in a series of blog posts that highlight stories from other cities and regions that have faced challenges comparable to that of the Syracuse region and the I-81 corridor.  To read other blog posts in the series, click here. Seattle’s Alaskan Way Viaduct is a double-decker highway with four lanes in each direction that carries State Route 99 through downtown along its Puget Sound waterfront. The viaduct was damaged by an earthquake »