According to
Federal-Aid Highway Program Guidance on High Occupancy Vehicle (HOV) Lanes
August 2008
http://ops.fhwa.dot.gov/freewaymgmt/...er3.htm#chp3b2
"Inherently low emission vehicles (ILEV) and low emission and energy-efficient vehicles - 23 U.S.C. 166(b)(5)
This section extends the existing exemption for ILEVs and adds another exemption for low emission and energy-efficient vehicles. Until September 30, 2009, States may allow ILEVs and vehicles certified and labeled as low emission and energy-efficient vehicles (including alternative fuel vehicles) that do not meet the established occupancy requirements to use HOV facilities so long as the State establishes procedures to enforce the restrictions on the use of the facility by these vehicles. These vehicles may be tolled, but, unlike HOT vehicles, the toll is not required. After September 30, 2009, the States must discontinue use of their HOV lanes by such vehicles."
italics are the US DOT not mine.
Federal-Aid Highway Program Guidance on High Occupancy Vehicle (HOV) Lanes
August 2008
http://ops.fhwa.dot.gov/freewaymgmt/...er3.htm#chp3b2
"Inherently low emission vehicles (ILEV) and low emission and energy-efficient vehicles - 23 U.S.C. 166(b)(5)
This section extends the existing exemption for ILEVs and adds another exemption for low emission and energy-efficient vehicles. Until September 30, 2009, States may allow ILEVs and vehicles certified and labeled as low emission and energy-efficient vehicles (including alternative fuel vehicles) that do not meet the established occupancy requirements to use HOV facilities so long as the State establishes procedures to enforce the restrictions on the use of the facility by these vehicles. These vehicles may be tolled, but, unlike HOT vehicles, the toll is not required. After September 30, 2009, the States must discontinue use of their HOV lanes by such vehicles."
italics are the US DOT not mine.
Comment