Posts about Hybrids

Hybrid buses average around 4 MPG, while diesel buses average 3.5 MPG and compressed natural gas (CNG) buses average 3 MPG. The Metrobus fleet includes 1,530 buses of 15 different models of varying capacity and fuel type. (See a slideshow of the different bus models below.)

The newest buses come in two different models, the 2009 New Flyer and the 2011 New Flyer Xcelsior. These buses have slightly less capacity than the diesel ones but there are 412 of these buses, comprising about one-fourth of the total fleet.

In addition to the hybrid electric buses, Metro operates 460 CNG buses. Because they require special fuel, they can only be stored at Metro's bus garages at Bladensburg and at Four Mile Run in Arlington. Some of the CNG bus models have luggage racks and service Metro's airport routes to Dulles and BWI.

Metro also operates three longer articulated bus models and one short model. Two of the articulated models are versions of the New Flyer hybrid bus and the third is an older diesel model. Articulated buses must use the Northern bus garage near the former Walter Reed site, the Montgomery bus garage in Rockville, or the Bladensburg garage in northeast DC to accommodate the extra length.

The articulated buses run on high capacity routes like the S1, 70 and X2. The short bus is an older diesel model and runs on lower ridership routes like the D2 and M4.

The oldest buses in Metro's fleet are 15 year-old diesel models. The average lifespan of these buses is 15 years, so many of the oldest ones are ready for replacement. This 15-year lifespan is longer than the Federal Transit Administration's 12-year minimum retirement age for heavy duty buses but the Metro board uses extended specifications (see bottom of page 25) to procure longer lasting buses.

Metro rehabilitates all buses around their mid-life point and performs about 100 bus rehabs per year. Rehabs don't extend the lifespan, but Anderson said mechanics examine almost every part of the bus to prevent breakdowns. This process costs about $110,000 per bus.

Metro has 104 of the 2011 New Flyer Xcelsior hybrid buses and has added about 102 New Flyer hybrid buses per year between 2008 and 2010. There are more than 300 of the oldest diesel models in the fleet but Anderson said Metro doesn't expect to replace all the diesel buses until 2017, which means some buses could be 20 years old at retirement.

Buses that old would be not that unusual. Metro still had 19-year old bus models in the fleet in June 2009, but those buses are no longer in service. As Metro continues to face budget constraints, it's not surprising that some buses will remain in service beyond their target life.

Here are photos of each of Metro's bus types. All photos from WMATA.

Recently I had a chance to test this presumption. I was crossing over I-66 on the pedestrian overpass near Madison Manor Park (map).

I tried to count how many cars were scofflaws but soon realized that it was difficult to tell if there was a child in the back seat or not. Also, many of the cars had the clean-fuel license plates

From this vantage point, the license plates could be read fairly easily, so I chose to count the plates instead. Traffic seemed to be traveling about 30-40 miles per hour, slower than free-flowing.

Plates with CF, CX, CY or CZ are exempt from the HOV requirement. (One can have a vanity plate exempted, too, but there were few of these; but how should one count the car with the plate GOVEGAN?) The following cars passed between 8:04 and 8:10 AM:

• 333 cars: 67 with clean-car license plates; 266 without.
  
• 1 motorcycle
  
• 2 buses
  
• 1 18-wheeler! (which are illegal on this highway)
  
• 1 eastbound 6-car Metro train

Of the cars, 67 had clean-fuel license plates, approximately 20%.

Here's some quick math extrapolating to an hour and making some assumptions:

• 2700 HOV cars with 2.2 riders = 6,000 people
  
• 670 clean-fuel cars with 1.1 riders = 750 people
  
• 20 buses with 40 people = 2,000 people
  
• 10 Metro trains with 800 riders = 8,000 people

The clean-fuel cars represent less than 5% of the people being transported along this corridor but represent 20% of the cars. Would removing that 20% increase flow enough or more than enough to make up the difference? Would increased flow entice more HOV cars onto I-66?