2.2 Arterial HOV Facilities

Reduce emissions by decreasing VMT and increasing average speeds on the lane.

Description

Separate lanes on controlled access highways are created for vehicles containing a specified minimum number of passengers. The lane may be concurrent flow, be barrier/buffer separated, or have a separate right-of-way.

Application

Roadways in areas of traffic congestion with sufficient available right-of-way.

$$\text{Daily Emission Reduction (grams/day)} = A + B + C + D$$

$$A = V_{H,A} \times (\mathit{EF}_{B} - \mathit{EF}_{H,A}) \times N_{\mathit{PH}} \times L$$

Change in running exhaust emissions from vehicles shifting to HOV lane

$$B = (V_{\mathit{GP},B} \times \mathit{EF}_{B} - V_{\mathit{GP},A} \times \mathit{EF}_{\mathit{GP},A}) \times N_{\mathit{PH}} \times L$$

Change in running exhaust emissions of vehicles in general purpose lanes as a result of vehicles shifted away from general purpose lanes

$$C = \mathit{VT}_{R} \times \mathit{TEF}_{\mathit{AUTO}}$$

Reduction in auto start exhaust emissions from trip reductions

$$D = \mathit{VMT}_{R} \times \mathit{EF}_{B}$$

Reduction in auto running exhaust emissions from trip reductions

$$\mathit{VT}_{R} = N_{P} \times (F_{T} \times F_{T,\mathit{SOV}} + F_{\mathit{RS}} \times F_{\mathit{RS},\mathit{SOV}}) \times 2 \ \text{trips/day}$$

Number of HOV users multiplied by the sum of the fraction of users selecting transit multiplied by the percentage that previously drove SOVs added to the fraction of users selecting ridesharing multiplied by the percentage that previously drove single-occupant vehicles multiplied by two trips per day (round trip)

$$\mathit{VMT}_{R} = \mathit{VT}_{R} \times \mathit{TL}_{W}$$

Number of vehicle trips reduced multiplied by the average auto trip length

Variables	(Unit)	Definitions
$\mathit{EF}_{B}$	(gram/mile)	Speed-based running exhaust emission factor before implementation (NOX, VOC, PM, or CO)
$\mathit{EF}_{\mathit{GP},A}$		Speed-based running exhaust emission factor after implementation of HOV facility (general purpose lanes) (NOX, VOC, PM, or CO) (estimate)
$\mathit{EF}_{H,A}$		Speed-based running exhaust emission factor on HOV facility (NOX, VOC, PM, or CO) (estimate)
$F_{\mathit{RS}}$	(percent)	Percentage of people attracted to the HOV facility using rideshare
$F_{\mathit{RS},\mathit{SOV}}$	(percent)	Percentage of people attracted to the HOV facility using rideshare that previously were vehicle drivers
$F_{T}$	(percent)	Percentage of people attracted to the HOV facility using a transit vehicle
$F_{T,\mathit{SOV}}$	(percent)	Percentage of people using a transit vehicle that previously were vehicle drivers
$L$	(mile)	Length of HOV facility
$N_{P}$		Total number of expected people using the HOV lanes per day
$N_{\mathit{PH}}$		Number of peak hours (AM and/or PM)
$\mathit{TEF}_{\mathit{AUTO}}$	(grams/trip)	Auto trip-end emission factor (NOX, VOC, PM, or CO)
$\mathit{TL}_{W}$	(mile)	Average auto trip length
$V_{\mathit{GP},A}$		Average hourly volumes on general purpose lanes during peak hours after implementation of HOV facility
$V_{\mathit{GP},B}$		Average hourly volumes on general purpose lanes during peak hours before implementation of HOV facility
$V_{H,A}$		Average hourly volumes on HOV lanes during peak hours
$\mathit{VMT}_{R}$		Reduction in daily automobile VMT
$\mathit{VT}_{R}$	(trip)	Reduction in number of daily automobile vehicle trips (estimate)

Source: CalTrans (Texas A&M Transportation Institute)