Local press picks up on speed-$ tradeoffs in TX130S concession
By Peter Samuel
Common speed sign on French autoroutes (motorways) 130km/hr (81mph) dry conditions, 110km/hr (68mph) in the wet
Seguin jog on TX130-S
8,000ft (2.44km) bar to map
"Safety for sale" is the slogan being used by critics of provisions in the Cintra-Zachry toll concession which provide for higher returns to the state if higher speed limits are posed - on which we got the scoop last week.
The Austin American-Statesman quotes Judith Stone of Advocates for Highway and Auto Safety a naderite lobby group in Washington DC saying: "it's a violation of public health responsibilities on the part of the state... Following on the heels of raising the speed limit to 80 on some segments of the interstates, it's very disturbing. It sounds like safety's for sale in Texas."
85mph for TTCs
Phil Russell director of the turnpike division of TxDOT says they are working on design standards for the Trans Texas Corridors (TTC) which would make them as safe at 85mph (137km/hr) as regular expressways are at 70mph (113km/hr). If TX130 is incorporated into TTC35 - as seems likely - it might be eligible for 85mph signing though that decision would ultimately be made by the Texas legislature. The concessionaire has no control over speed signing.
Irresponsible not to ask more for taxpayers for higher speed
Russell says that since higher speed on TX130-South would boost the concessionaire's revenue and profitability it would be irresponsible for the state not to seek a share of the extra revenues on behalf of taxpayers - which is what the speed-concession fee/revenue sharing provisions of the concession do.
Gentler curves and grades
Higher design speeds are mostly a matter of longer sight distances when the road curves or encounters undulations in the landscape so it means gentler curves and grades. It also usually involves larger breakdown lanes on the right side and pavement offset from the leftside lane stripe to provide more pavement for an errant motorist to recover from wandering out of the lane - a 'lane departure' in the jargon. Still, in the end, there is a large subjective aspect to any judgment about what is safe and unsafe because of the variabilities of drivers, the road and conditions.
In many European countries the posted expressway/motorway speed is 130km/hr (81mph) in rural areas and during dry conditions for cars. There are lower legal speeds for trucks and in rain. Italy has some motorways with 150km/hr (93mph) posted and in Germany the autobahn often has no legal maximum though there is an advisory 130km/hr (81mph) max. Spain, Portugal, Greece, Switzerland and other European countries have 120km/hr (75mph) maxima, and the UK has 70mph (112km/hr). Enforcement of course varies enormously.
Accident and fatality rates show little correlation with posted speed limits.
Jogs in TX130S
The TX130 South looks likely from the maps provided to need lower speeds at a couple of places. Near the southern end at Seguin there is a jog involving a 90 degree turn southeast and then a 90 degree turn back southwest a few miles before the end of the concession route at I-10. There is also a less severe Lockhart jog with only one 90 degree turn on the western edge of the town of Lockhart.
These jogs reduce the land take needed for the highway because it is cutting across the grain of the square grid of local property boundaries and local roads. But the jogs hardly reflect the Trans Texas Corridor concept of a huge corridor heading inexorably for its distant objective at the state's borders. TOLLROADSnews 2006-07-11