I had the opportunity yesterday to ride the rail-replacement shuttle from Alewife to Harvard. (I’m not faulting the T for such shutdowns at all, maintenance needs to happen.) But the buses are run very inefficiently, and if the route was changed, it could halve the number of buses required to provide the service, cutting the cost of operating these buses by tens of thousands of dollars, and provide better service for most riders.

The issue is that while Alewife is a pretty straight shot from Harvard by rail, it isn’t by road. Somerville pushed hard to have Davis included in the Red Line extension in the 1980s, and the subway follows the old Fitchburg Cutoff from Davis to Alewife, less than a mile. But the bus route is longer: it runs out from Davis to Teele Square and Clarendon Hill, then turns on to the narrow-laned Alewife Brook Parkway (going inbound, this is a very tight turn for buses; the bus I was on was forced to drive over the sidewalk to make it) before running through the mess of an intersection at Route 2 and on to Alewife, a distance of more than two miles (with half a dozen traffic lights). And the buses here are mostly empty: on weekends, relatively few passengers board at the park-and-ride Alewife, with more coming from Davis and Porter squares.

Here’s how the buses operate currently (approximately):

0:00 leave Harvard Square
0:06 leave Porter Square
0:11 leave Davis Square
0:24 arrive Alewife

From Porter and Davis, this only amounts to a three to five minute delay versus the subway (plus a transfer penalty and traffic). From Alewife, however, it’s closer to a fifteen minute delay, since the trip from Davis takes so long. And even though the buses rumbling along Alewife Brook Parkway are mostly empty, the cost of operating a bus is the same whether it has 60 passengers on board or six, and there are often four empty buses lined up in a traffic jam on Alewife Brook Parkway waiting for the long light cycle at Mass Ave or Route 2.

Let’s assume the T uses 4 buses per train and that there’s a train every 8 minutes. That would mean that with a 48 minute round-trip operation time, there would be 24 buses on the route at any given time (this doesn’t include schedule recovery time at either end of the line, and turning time at the Bennett Alley end of the Harvard Tunnel, which are the same in both scenarios). Imagine if, instead, you had the following:

• Three buses leave Harvard with a destination of Davis stopping at Porter. With a busway, buses are able to turn at Davis, and by stopping in the busway will provide better passenger amenities there and provide a single stop in Davis.
• One bus leaves Harvard to Alewife. This bus could either run directly to Alewife via Concord Ave, or out to Porter on Mass Ave and then via Rindge to Alewife (coming back, buses would have to use the Concord Ave routing to get to Harvard). This is about a 10 or 11 minute trip.