Confirmed: Removing Cars from Great Highway is Good for the Environment

Multimodal Monarch

Oct 24, 2024 • 3 min read

The SF Estuary Institute just released a comprehensive report evaluating the different options on the table for cars on the the Great Highway, and environmental impact of each. Spoiler, "closing the roadway to cars entirely has the greatest and most immediate ecological benefits".

Ecological Opportunity Supporting Actions 1 Full Time Promenade 2 Partial Road Closure 3 Open Road Benefits to Nature and People Restore and revegetate Restore dune habitat    Reduces sand on roadway, decreases maintenance costs, and improves recreational experience Benefits wildlife in dune habitats Replace nonnative plants with ecologicallybeneficial landscaping   with limitations  with limitations Increases biodiversity and enhances habitats for native birds and pollinators Supports human health and strengthens emotional connection to the environment Plant larger shrubs and bushes  Provides shelter, nesting habitat, and food resources for wildlife Guides pedestrian traffic and limits trampling of habitat Protect habitat and improve recreation Reduce and adjust street lighting   with limitations  with limitations Improves wildlife and plant functioning, including navigation abilities of night-migrating birds Provides human health benefits Improve trash management practices    Reduces litter and nuisance species activity, improving overall visitor experience Install educational signage   Maintains recreational access while protecting sensitive habitat Educates visitors and encourages stewardship

The report is very clear that removing cars is the best option. Wildlife are significantly harmed by car noise, lights, and physical conditions. This sounds obvious, but trolls out there seem to think otherwise. Luckily, the science is on our side.

Additional benefits of road closure include enhanced recreational use due to reduced traffic. Outdoor recreation improves physical and mental health outcomes, and reduced traffic will increase pedestrian and cyclist safety. A vehicle-free Great Highway will create a better pedestrian and cyclist connection between Golden Gate Park and Ocean Beach, in alignment with the Ocean Beach Master Plan. Conversion of the Great Highway from a vehicle roadway to a promenade will provide immediate benefits to many species due to a reduction in harmful traffic-associated impacts. These impacts include wildlife disorientation or avoidance behaviors caused by traffic, noise, and artificial light, in addition to wildlife-vehicle collisions.

There are two major sections of potential benefits the report highlights. The first is dune restoration. While there is work that can be done at any time on restoring dune and removing nonnative ice plant/marram grass, planting larger native shrubs at the limit of sensitive areas is best done without cars around.

PLANT LARGER SHRUBS AND BUSHES SCENARIO: PEDESTRIAN PROMENADE WHY? A buffer of dune-scrub vegetation planted at the edge of restoration or sensitive areas can guide pedestrian access and limit vegetation trampling, protecting habitat. Multiple layers of vegetation are also beneficial for many species, providing shelter, nesting habitat, and food resources for birds, reptiles, and small mammals. Vegetative structure introduced by larger shrubs is particularly beneficial for invertebrates such as insects. SUPPORTING DOCUMENTS: Making Nature’s City Report; Ocean Beach Master Plan―Key Move 5, Strategic Action 5.8 A native shrub, yellow bush lupine, at Bodega Head State Park. Photo by David A. Hofmann, Creative Commons.

RESTORE DUNE HABITAT SCENARIO: PEDESTRIAN PROMENADE | PARTIAL CLOSURE OPEN ROAD WHY? Revegetation of the parkland strip (between the Upper Great Highway and the dune crest) with native dune species, such as beach wildrye (Leymus mollis), presents a valuable opportunity to increase native vegetation in an area with low existing native plant diversity. These plants would also support sand-trapping along the seaward portion of the Highway, reducing maintenance costs linked to sand encroachment. SUPPORTING DOCUMENTS: See Growing Resilience: Recommendations for Dune Management at North Ocean Beach for more recommendations regarding dune restoration, maintenance, and protection. WHAT’S HAPPENING NOW: Early propagation of key species― such as beach wildrye―is critical to making dune restoration feasible and successful. Since the publication of Growing Resilience: Recommendations for Dune Management at North Ocean Beach, several SF agencies have been collaborating to establish a wildrye propagation pilot study at Ocean Beach. Additional funding is currently being sought for further implementation.

REPLACE NON-NATIVE PLANTS WITH ECOLOGICALLYBENEFICIAL LANDSCAPING SCENARIO: PEDESTRIAN PROMENADE | PARTIAL CLOSURE | OPEN ROAD WHY? Ice plant and marram grass, which dominate the Highway’s median strip, are non-native, have low habitat value, and produce few food resources for local species. Removal of these plants would create space for ecologically beneficial plants that support wildlife and trap sand. There are benefits for humans as well: increased biodiversity has been linked to improved mental health and native flowering plants have been linked to reduced allergen sensitivity. The amount of benefit depends on the quality of replacement plantings: See Appendix Table 2 for expert recommendations on plant replacements. Revegetation can also incorporate nectar and fruiting plants that provide high-quality resources for species in the area. SUPPORTING DOCUMENTS: Growing Resilience: Recommendations for Dune Management at North Ocean Beach; Ocean Beach Master Plan; EcoHorticulture in the Presidio; Ecology for Health

Artificial lighting is harmful to a number of species. It is of course required if cars will be there at any time. Removing lighting helps wildlife, humans, and the city budget. Adjusting the color temperature of the remaining lighting also improves the situation.

REDUCE LIGHTING AMOUNT Decrease street lighting between dusk and dawn as much as possible, minimize light intensity, ensure lights are shielded, and remove unnecessary light fixtures SCENARIO: PEDESTRIAN PROMENADE | PARTIAL CLOSURE* | OPEN ROAD* WHY? A reduction in street lighting—a major source of artificial light at night —between dusk and dawn improves animal navigation and movement. Artificial light at night negatively impacts a range of wildlife, and is particularly disruptive to bats and migrating birds. Certain human health impacts, such as cancer risk and disruptions to melatonin production, have also been linked to artificial light at night. SUPPORTING DOCUMENTS: SF Standards for Bird-Safe Buildings; Ecology for Health; DA - IES Model Lighting Ordinance

CHANGE LIGHTING COLOR TEMPERATURE Adjust street lighting to a warmer light temperature SCENARIO: PEDESTRIAN PROMENADE | PARTIAL CLOSURE* | OPEN ROAD* WHY? Street lighting that has a cooler light temperature contributes more to night sky brightness, negatively impacts bird movement, and is generally disruptive to a many plant and animal species. SUPPORTING DOCUMENTS: Ecology for Health; DA - IES Model Lighting Ordinance The Great Highway at night. Photo by Peter Thoeny Creative Commons BY NC-SA 4.0 * Asterisks indicate the scenarios in which a supporting action can only be partially implemented. In scenarios allowing vehicles, lighting will still need to meet the needs of a vehicle roadway, limiting possible lighting adjustments.

It's worth noting that cars are uniquely bad right next to the ocean. Normally, oil and particulates washing into the stormwater system will go through the treatment plants (like the one near the crumbling Great Highway extension). But that close to the ocean, the toxic chemicals go directly into our ground and water. It's not good.

The report mentions a few other improvements, so it's worth checking out. But this mostly confirms what we already know. Removing cars improves lives for humans and nature. Traffic tends to evaporate as people seek other modes, and everybody benefits. K is endorsed by every other environmental org as well, so this is consistent. Yes on K!

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