In a message dated 9/9/02 7:22:33 PM, [log in to unmask] writes:
<< I'm sorry to have to question Peter's number about only 30% of the traffic
being on motorways. As I looked at the national highway statistics a few
years ago. I recall more like 70% of VMT is on the interstates and arterials,
with about 30% on local roads. >>
Memory plays tricks. USDOT's <<Highway Statistics 2000 pV-51>> shows 846b
vmt/yr on urban interstate, other urban freeways and expressways and rural
interstates which is the best measure I can see of motorways in US (56,000mi
approx) albeit a conservative one since there is a considerable mileage of
rural non-interstate motorways. Total VMT on all US roads (3,951,000mi) is
2,767b so motorways carry about 30 percent of the VMT. The motorways have
7,100 fatalities out of 42,400 or 17 percent. Death rates are 7100/846 or
8.4/bvmt and non-motorways are 35000/1920 or 18.2/bvmt. Interestingly
tollroads are better (about 6 fats/bvmt) than free motorways so their
generally higher standards help too. 650bvmt of travel are done on other
principal arterials (OPAs) on which there are 9,900 fatalities. At the
motorway fatality rate of 8.4 there would be 5460 fats on the OPAs so the
upgrade of OPAs to motorways could save 4400 lives per year - about 1.5
9/11s/year! I suggest access control and grade separation save lives on a
scale that make other road safety measures like DRLs minor sideshows by
comparison. It would be nice to have some discussion of this from our road
safety establishment, but mention of it seems to generate more expressions of
outrage than answers, which suggests to me they don't have answers.
Downside of DRLs are extra fuel consumption, extra glare to cope with for
drivers in low slung vehicles vs oncoming pickups and other trucks, flat
batteries from forgetting to switch lights off at journey's end, reduced
headlight life, higher battery wear, and no proven value in normal
conditions. In grey or rainy conditions - New Zealand most of the time? –
sure DRLs may make sense, but in bright conditions in N America outside
Washington state, or Australia outside Tasmania the value has not been
established. Being in diplomatic mode with respect to important allies of
this nation I desist from any comment on British needs, except to recommend
DRLs to the Irish. PSamuel
