A New 101/580 Connection Poses Risks

At last week’s Transportation Authority of Marin (TAM) meeting, the Board decided to spend half a million dollars studying a new direct connection from northbound Highway 101 to the Richmond-San Rafael Bridge.

At first blush, this makes sense.  It’s unusual for two major highways like 580 and 101 to meet but only allow for a connection in one direction.  The result is that Sir Francis Drake, a local two-lane road with stop lights, effectively becomes part of the highway system.  The intense congestion on Drake spills onto Highway 101 gumming up the northbound flow of traffic in the evenings. 

However, a new direct connection from Highway 101 northbound to the Richmond-San Rafael Bridge could create serious problems for San Rafael.

It’s estimated that this connection (somewhere just north of Bellam) would divert about 1/3 of the traffic that currently marches down eastbound Sir Francis Drake in the evening.  That diverted traffic wouldn’t vanish.  It would simply be relocated to San Rafael.  

At the moment, backups in San Rafael on the approach to the Richmond-San Rafael Bridge sometimes extend beyond to the 580 on-ramp and into southbound Highway 101.  If a higher volume of traffic were to flow into the approach, these traffic backups could more frequently extend beyond the Heatherton on-ramp, which would cut off the flow of traffic leaving Downtown.  The result would be more downtown gridlock.    

San Rafael would also have to add a giant “Los Angeles style” freeway ramp just like the kind that was rejected by Corte Madera as unsightly and unsuitable.  It’s worth asking why something that is not OK for Corte Madera is fine for San Rafael.

This project won’t do much for overall traffic congestion in Marin County, either.  Many speakers at last week’s TAM meeting were eloquent in describing the root of problem – the limited capacity of the Richmond-San Rafael Bridge. 

Unless Caltrans allows for the bridge’s breakdown lane to be used as a third lane for vehicular traffic, no amount of new freeway structures built up on the Marin County side of the Bay are going to make much difference. 

It was with this futility in mind that the TAM Board decided not to build big, high-impact, freeway structures in Corte Madera.  This same logic should apply in San Rafael. 

Mayor Phillips did his best at the TAM meeting to have the City of San Rafael control the 101 to 580 connector study.  The TAM Board said no.  Ultimately, this might be for the best, since San Rafael’s objectivity may be doubted and since the issue could become another lightning rod.  Still, San Rafael staff must keep a watchful eye on the study to ensure that it takes into account all of the potential impacts and risks.