HOT Lanes and VMT

Caltrans’ guidance on induced travel can be interpreted as treating high-occupancy toll (HOT) lanes similarly to high-occupancy vehicle (HOV) and general purpose (GP) lanes, based on VMT generation. However, adding a HOT lane is more complicated and is addressed more directly in the sections below. 

Per Section 5.1.1 of the Transportation Analysis under CEQA (TAC), conversion of existing general-purpose lanes (including ramps) to managed lanes or transit lanes or changing lane management in a manner that would not substantially increase vehicle travel would not likely lead to a measurable and substantial increase in VMT and therefore generally should not require an induced travel analysis per OPR’s Technical Advisory.However, a project that adds a new HOV lane could induce as many vehicle miles traveled (VMT) as a new GP lane would. Please see further explanation on the HOV lanes and VMT hot topic.

While much evidence supports the general HOV lane addition finding, a HOT lane addition appears more complicated because of tolls. A new HOT lane is more permissive than an HOV lane, as single-occupancy vehicles (SOV) can pay their way in. A further complication is revealed in data collected by Caltrans District 7 in the Los Angeles metro region related to their express lane projects on I-10 and I-110. The data documents substantial violation rates in self-selection of occupancy by transponder users to avoid toll payment and concludes that introducing express lanes has led to substantially fewer carpools and person throughput in both corridors.

However, some circumstances may result in a more positive impact on VMT, from adding a HOT lane to an existing freeway when compared to adding an HOV or GP lane.

Availability of toll revenue for VMT-reducing strategies

If revenues are committed to VMT-reducing strategies, they could offset induced travel associated with the HOT lane addition. It is essential to have a commitment and not a “promise” or “intention” to provide revenue for VMT mitigation activities. This commitment would need to be documented in the Environmental Commitments Record (ECR) and in the financial planning for the HOT lane addition, including a strategy for making up any shortfall in revenue projections.  

Commitment to toll adjustment to ensure VMT reduction

There needs to be a strong commitment to adjusting toll levels (and/or HOV policies such as occupancy requirements and clean air vehicles (CAV) discounts) to achieve volumes consistent with negative or neutral VMT. By the time the final environmental document is circulated, a procedure for exactly what would trigger a change in the toll level (and/or HOV policy), how often the reviews would take place, and how the different strategies (higher tolling and/or HOV requirements) would need to be determined.

GP to HOT conversion + HOT addition together

Another strategy that may be proposed is to convert an existing GP lane to a HOT lane while also adding another HOT lane at the same time (6 GP lane existing freeway to 4 GP lanes + 4 HOT lanes, for example). The potential for VMT inducement may be moderated and/or reduced by eliminating the two GP lanes. Still, it would also have to account for the possibility of induced VMT related to the overall addition of lanes available. This strategy would require a thorough analysis of the mix of traffic on the existing facility, the potential for carpool formation, and other issues such as transit priority (see below).

Provision of transit priority

If the HOT lane addition provides for transit vehicle priority that does not currently exist, that could be a consideration in the approval of a project and the mitigation of the induced VMT. Transit priority could include adding features that go beyond the HOT lane addition itself (signal pre-emption/prioritization at ramps, bypass lanes on ramps). It would be necessary in this case to confirm the improved service that either exists or would be put in place in conjunction with the HOT lane addition by receiving a written commitment from the appropriate transit operator. Transit priority should also include an analysis of the improved transit service (reduced travel time, increased travel time reliability and frequencies, expected increased ridership from service expansion, etc.). Providing only the opportunity for transit priority would not impact the VMT performance of the HOT lane addition.

Policy benefit of expanding pricing on the highway system

One of the most difficult VMT benefits for a HOT lane addition would be the advancement of pricing as a long-term strategy for optimal highway system operation. If the highway system ultimately transitions to a fully priced network, there could be systematic VMT reduction through more efficient driver decisions and actions. While this may primarily be caused by the predicted gradual loss of fuel tax revenue over time due to the transition to zero-emission vehicles and other technological changes, a mileage-based user fee that may be implemented under such system-wide change could lead to more efficient traveler choices and ultimately reduce the number of vehicle trips.

However, the incremental approval of HOT lane additions based solely on the promotion of this policy could lead to more than just short-term VMT impacts, as the predictions for the timing of this type of system-wide transition are generally longer-term.

Other important considerations

While the above-described circumstances can affect the VMT outcomes of a proposed HOT lane addition, there are other issues worth considering that can impact VMT but generally have broader implications for HOT lane addition projects.

Violation and enforcement issues

Issues with enforcing HOV occupancy and toll evasion have been reported throughout the system where these strategies have been implemented. While it is likely impossible to eliminate all violations, Caltrans has stated goals to limit HOV occupancy violations that are clearly being exceeded in some locations (such as those described above in Caltrans District 7). As for toll evasion, there is also evidence that violation levels are unacceptably high (or at least concerning) to many toll operators across the state. While efforts to better address these issues are underway, and this situation goes beyond impacts to VMT, it does raise the importance of a full review of any violation/enforcement actions on VMT mitigation efforts for HOT lane addition proposals. Discussion of potential violations/enforcement should be included in environmental documents that seek to use lane management as a VMT reduction strategy.

Equity

Some question the equity impacts that any type of pricing strategy may bring to the highway system by requiring underserved users of the system to pay an additional fee or toll. However, this situation is more complex as “free” lanes are not necessarily equitable. Carefully designed pricing strategies can improve equity by increasing choice for underserved users. Lower-income users may use a HOT lane to increase reliability during critical trips. Additionally, pricing systems allow the redistribution of toll revenues towards rebates, discounts, or the transferring of revenues to transit and mobility improvements in the corridor. Implementing tolls as a demand management measure can play a role in paying for transit and reducing the impact of pricing on low-income individuals. Equity must be considered in any redistribution of benefits.

While there may be different perspectives regarding the equity impacts of pricing strategies on the highway system, any project that includes pricing needs to address equity implications and ensure that pricing is applied in a way that does not result in disproportionate impacts.

Importance of thorough consideration and documentation

Whether a HOT lane addition is claiming to fully mitigate induced travel or proposing a Statement of Overriding Considerations for any residual VMT inducement that is not fully mitigated, documentation of the thorough review, analysis, and implementation of the VMT reduction strategies is necessary.

 Issues addressed in project documentation include:

• Tolling scheme and its direct impact on induced VMT
• Financial plan highlighting the use of revenues for VMT-reducing activities
• Documentation of commitments with external organizations regarding tolling, revenue, and VMT-reducing strategies
• Enforcement provisions on VMT containment/reduction
• Description of the regional plan for tolling the highway system, including the proposed timeline for implementation
• Operational considerations (HOV occupancy, hours of operation, etc.)
• Equity analysis directly related to the proposed tolling scheme
• Other issues not included here that may have an impact on induced travel resulting from the addition of a HOT lane