We need your help
We need the public’s help at Assateague. We need data on any horse-vehicle interactions (fatal, injured, or near-miss) at Assateague Island. We need the exact location, as far back as possible, including near misses. Horses often follow specific trails and paths throughout Assateague, and our ability to pinpoint areas of concern can help prevent future interactions. At the bottom of this page are two maps, one general, the other Google Earth- please feel free to download, add your observation and email us or DM on Facebook.
There has been a great deal of anger and sadness following the recent vehicle strikes on Assateague, and those reactions are completely understandable. When several animals are struck within a short period of time, people naturally look for an explanation, something that changed, something that failed, or something that might have prevented it. I am writing this because I want to help prevent the next horse collision on Assateague Island. I have offered my expertise as a biostatistician to help analyse the collision data and identify patterns that may point toward practical, evidence-based prevention. I care deeply about these horses, but concern alone will not solve the problem. Good data, careful analysis, and realistic mitigation might. I have been in touch with the Assateague Island Alliance.
Most importantly, science does not support assigning wildlife-vehicle collisions to a single cause. These collisions are multifactorial, involving wildlife behaviour, driver behaviour, visibility, traffic volume, road design, speed, time of day, and surrounding habitat (Gunson et al., 2011; Shilling & Waetjen, 2015).
There is a very real and serious wildlife-vehicle collision problem on Assateague Island. However, this problem is not new. In September 2019, the National Park Service reported that 34 horses had been killed by vehicles and another 17 horses had been injured by vehicles in collisions on the Island since 1982. The Park Service reported that there were 51 documented wildlife-vehicle collisions on the Island since 1982 (National Park Service [NPS], 2019). More recently, in 2021, Moonshadow, a pregnant mare, was killed in a collision on Bayberry Drive. Her foal was seriously injured in the crash. The total number of horses to have been struck by vehicles on the Island was reported to be 53 horses, with 35 of them killed in the resulting collisions (Walburn Viviano, 2021).
The recent cluster of wildlife-vehicle collisions on Assateague Island occurred within a relatively short time frame. In the last six weeks, three horses have been involved in collisions with vehicles on the Island. Two of them were killed in the incidents. Recently, Susi Solé was killed by a vehicle on Bayberry Drive on August 13, 2026. The incident occurred just 13 days after another horse had been killed in a collision with a vehicle on the Island (Sweigart, 2026). In response to recent collisions, the National Park Service (NPS) is investigating additional measures to prevent further incidents involving wildlife and vehicles on the Island. A cluster of wildlife-vehicle collisions does not have to be caused by the same factor(s) that caused the other collisions in the cluster. Therefore, it is not sufficient to conclude that a cluster of wildlife-vehicle collisions has occurred, and then to stop investigating.
Banning Cars?
As was mentioned previously, there are valid reasons for banning cars from Assateague Island after the recent deaths of several horses. The National Park Service has the authority to ban all vehicles from park areas. However, a permanent, park-wide ban on cars would be far more complicated than simply closing a road or two and then returning to ‘business as usual’ after a temporary period. Already, the National Park Service restricts a variety of activities and uses throughout Assateague Island National Seashore. For example, the over-sand vehicle zone is occasionally closed temporarily for wildlife management purposes. The 36 C.F.R. § 1.5 authority is used to restrict a variety of activities throughout the park.
Furthermore, as previously noted, motor-vehicle travel in national parks is permitted only on park roads and designated routes. Thus, such travel does not constitute an entitlement to travel wherever and whenever one pleases within a national park. Any such ban would likely have a major impact on visitor use of the park and would have to be justified in writing, be subject to public notice, and would likely require additional planning and environmental analysis beyond the authority provided by 36 C.F.R. § 1.5. In fact, the Superintendent’s Compendium for Assateague Island National Seashore states that for major or controversial restrictions on activities, in addition to the authority provided by 36 C.F.R. § 1.5, additional procedures such as formal justification, public notice, planning, and environmental analysis are required.
Therefore, even though a complete car ban would be legally possible, it would be operationally very difficult to carry out. Instead, restrictions on where, when, and how cars could travel in parts of the park where horses are frequently present would be both legally feasible and already consistent with the powers the National Park Service currently exercises at Assateague Island National Seashore. The collision history of horses and cars at Assateague Island would, by itself, not provide a basis for concluding that a complete car ban would be the best solution to the problems that have arisen at the park. Instead, such a history simply raises the question of whether consideration should be given to a variety of other measures that could have the same effect as a complete car ban but which would not have the same impact on visitor use of the park.
What can be done?
Some examples of such measures include restrictions on nighttime driving by cars, temporary closures of park roads for periods of time when large numbers of horses are using sections of the park’s road system, measures to reduce the speed of approaching cars, measures to control the flow of traffic on park roads and to redistribute the effects of any collisions that might occur, restrictions on the number of cars that could travel on park roads during peak hours of the day, and a ban on cars from certain sections of park roads during periods of time when large numbers of horses are present in those areas of the park. All of these measures are consistent with the mission of the National Park Service and the current management of Assateague Island National Seashore, as outlined in the park’s General Management Plan. The General Management Plan for Assateague Island National Seashore notes that recreation must be resource-compatible. Therefore, while a complete car ban would be legally possible, it would not be the most sensible measure to consider, and instead a number of other, more targeted measures should be considered in order to determine whether or not they would be as effective in reducing the number of collisions between cars and horses as a complete car ban.
Most research on wildlife-vehicle collisions recognises that wildlife-vehicle collisions occur in spatial clusters or hotspots (Gunson et al., 2011). Therefore, the factors explaining wildlife-vehicle collisions in hotspots can vary. For example, factors that explain collisions in one hotspot may not explain collisions in another hotspot of similar wildlife species and road configuration. As such, wildlife-vehicle collision mitigation is best conducted on a site-by-site basis using information specific to each site (Gunson et al., 2011). In addition, research has found that even wildlife-vehicle collision hotspots are not fixed in space over time (Shilling & Waetjen, 2015).
In wildlife-vehicle collision studies, time of year and day of year have also been found to influence collision frequency. Studies have found species-specific patterns in the temporal distribution of wildlife-vehicle collisions. Therefore, for the Assateague horses, a study of wildlife-vehicle collision occurrence would be valuable for identifying the days and times of the year when the greatest number of collisions is expected.
Pollard and Grewar (2020) investigated 4,341 horse-related road incidents in the UK involving ridden or loose horses and found significant spatial and temporal clustering. In terms of factors influencing collision severity, driver behaviour, especially excessive speed, was found to be particularly fatal to horses. Importantly, loose horses (free-roaming ponies) were found to have significantly greater odds of fatal injury than their ridden counterparts.
Assateague is unique
The information presented above addresses wildlife-vehicle collisions in general and horse-vehicle collisions in general, but not specifically the wild Assateague horses. Some of the information and corresponding data may be applicable to the Assateague horses, but others would not. Several variables have been measured in previous studies of wildlife-vehicle collisions, including speed, visibility, location, time, animal behaviour, and driver behaviour.
1) Well-travelled paths. Wild horses do not move randomly across the landscape. Free-ranging horses establish home ranges and habitually use areas and travel routes in response to water, forage, terrain, season, and other environmental conditions (Hennig et al., 2018; Ostermann-Kelm et al., 2009; Schoenecker et al., 2023). On Assateague specifically, individual bands occupy recognisable home ranges, and long-term research has demonstrated patterned habitat use related to temperature, wind, habitat type, and biting-fly pressure (National Park Service, 2023; Powell et al., 2006). This raises a testable possibility that some road crossings may occur repeatedly where established horse travel routes intersect Bayberry Drive or Route 611.
©Karen McLain Studio, 2014
©Karen McLain Studio, 2017.
2) Reducing the speed limit on park roads is not going to result in drivers travelling at lower speeds. Riginos and colleagues (2022) studied the effect of reducing the nighttime speed limit on a section of highway where mule deer frequently cross. They found that, on average, drivers’ speeds were reduced by only about 2%. They concluded that there was little evidence that reducing the posted speed limit on park roads would reduce wildlife-vehicle collisions.
3) Warning systems also have mixed results. Research conducted by Sullivan et al. (2004) in highway migration corridors for mule deer found that temporary, highly visible warning signs with or without flashing amber lights decreased deer-vehicle collisions by about 50% in the treated areas. However, the decrease in collisions was unsustainable because drivers eventually ignored the warning signs. Thus, the warning signs would have to be made highly visible on a temporary basis or be dynamic to be effective.
4) Road-mortality mitigation: Rytwinski et al. (2016) conducted a very large meta-analysis of all sorts of interventions for reducing wildlife roadkill. On average, there was a 40% reduction in wildlife roadkill across interventions, though substantial variation existed among intervention types. For large mammals, the best interventions were fencing and crossing structures. Animal-detection systems seemed to hold a lot of promise but were not yet as effective as, for example, reflectors (which are less expensive to put up).
National Parks and the Assateague Island Alliance
For those unfamiliar with Assateague, note that the National Park Service (NPS) manages the horses on the Maryland side of the Island as a wildlife population and manages the roads, visitors, etc. within the park. Assateague Island Alliance (AIA) is the official friends group of the park and supports the work of NPS by fundraising, education, volunteers, equipment and conservation programs and activities within the park (NPS, 2015)
The horses are being managed as a wildlife population, and NPS continues to work to reduce food conditioning and habituation of the animals in the park’s developed areas. AIA has been working to help the horses of Assateague by raising $100,000 to replace 222 of the park’s picnic tables with wildlife-resistant food-storage tables. In addition to the work to develop wildlife-resistant food-storage tables, AIA’s funding of the horse-management interns, equipment and visitor-education programs has been a critical component of the Island’s horses’ management as a wildlife population.
Reasonable mitigation to evaluate could include:
- Map every collision and near miss event at the exact GPS location to establish hotspots.
- Document the time of day, lighting, weather, traffic volume, direction of travel on Bayberry Drive and Route 611 and road conditions for each collision or near collision.
- Measuring actual vehicle speeds, rather than relying only on posted limits.
- Targeted enforcement and/or traffic-calming measures at locations where speeding or excessive approach speed have been documented.
- Dynamic or flashing warning systems during identified high-risk periods or in collision hotspots.
- Nighttime visibility measures (such as improved lighting or increased sight distance) in areas where collisions and near collisions are occurring.
- Continue to reduce food-conditioning and habituation around developed areas.
- Recording data on the horses that are struck by vehicles, including the identity of the horses, their bands, their behaviour, and the frequency of their use of the road.
- Using before-and-after data to establish whether a given intervention does reduce collisions, as opposed to simply being assumed to do so (Rytwinski et al., 2016).
Using statistics to predict future horse-vehicle interactions
Looking at the most recent incidents first and going into as much detail as possible to improve the data currently being collected. We do not have to treat every horse strike as random. We can build a prediction model that includes season, time of day, traffic volume, and location:
For example, we can look at Bayberry Drive to see if there are any repeats of strikes in the same locations. In addition, we can look at strikes that occur during nighttime hours and at the speeds vehicles are travelling to see whether they are travelling at excessive speeds. Finally, we can look to see which horses are repeatedly occupying the roadways.
In plain English: if the data show that strikes are more common in summer, at night, on Bayberry Drive, and during heavy traffic, the model combines those factors to estimate when collision risk is highest. That is much more useful than simply saying, “another strike will probably happen.” It tells us when and where prevention should be concentrated.
That is how the problem becomes manageable. Three strikes within roughly six weeks are an important signal. It is not yet an explanation. Identify patterns in collisions, measure variables of interest, introduce a few ‘good’ interventions and test for ability to reduce future collisions. Supporting AIA, supporting the National Park Service, and asking for stronger evidence-based collision prevention are not mutually exclusive. The goal should not be to identify somewhere to direct anger.
Our goal here on this blog is to prevent the next horse collision on Assateague Island. Thank you for your time and consideration. Together we can.
Dr Meredith Hudes-Lowder, Biostatistician
August 16, 2026
References
Assateague Island Alliance. (n.d.). Donations and Protect initiatives. Assateague Island Alliance.
Gunson, K. E., Mountrakis, G., & Quackenbush, L. J. (2011). Spatial wildlife-vehicle collision models: A review of current work and its application to transportation mitigation projects. Journal of Environmental Management, 92(4), 1074–1082. https://doi.org/10.1016/j.jenvman.2010.11.027
Hennig, J. D., Beck, J. L., & Scasta, J. D. (2018). Spatial ecology observations from feral horses equipped with global positioning system transmitters. Human–Wildlife Interactions, 12(1), 75–84. https://doi.org/10.26077/z9cn-4h37
King, S. R. B., & Schoenecker, K. A. (2022). Application of tail transmitters for tracking feral horses as an alternative to radio collars. Wildlife Society Bulletin, 46(4), e1338. https://doi.org/10.1002/wsb.1338
National Park Service. (2015). Join our friends: Assateague Island Alliance. Assateague Island National Seashore.
National Park Service. (2019, September 30). Assateague Island National Seashore wild horse fatality. Assateague Island National Seashore.
National Park Service. (2022, May 2). Relocation of an aggressive and highly food-conditioned horse from Assateague Island National Seashore to the Cleveland Amory Black Beauty Ranch. Assateague Island National Seashore.
National Park Service. (2023, May 16). Assateague’s wild horses. Assateague Island National Seashore. https://www.nps.gov/asis/learn/nature/horses.htm
National Park Service. (2026). 2026 annual horse population update for Assateague Island National Seashore. Assateague Island National Seashore.
Ostermann-Kelm, S. D., Atwill, E. A., Rubin, E. S., Hendrickson, L. E., & Boyce, W. M. (2009). Impacts of feral horses on a desert environment. BMC Ecology, 9, 22. https://doi.org/10.1186/1472-6785-9-22
Pollard, D., & Grewar, J. D. (2020). Equestrian road safety in the United Kingdom: Factors associated with collisions and horse fatalities. Animals, 10(12), 2403. https://doi.org/10.3390/ani10122403
Powell, D. M., Danze, D. E., & Gwinn, M. A. (2006). Predictors of biting fly harassment and its impact on habitat use by feral horses (Equus caballus) on a barrier island. Journal of Ethology, 24(2), 147–154. https://doi.org/10.1007/s10164-005-0174-2
S. Raymond, A. L. W. Schwartz, R. J. Thomas, E. Chadwick, S. E. Perkins, “Temporal patterns of wildlife roadkill in the UK,” PLOS ONE, vol. 16, no. 10, p. e0258083, 2021. https://doi.org/10.1371/journal.pone.0258083
C. Riginos, E. Fairbank, E. Hansen, J. Kolek, and M. P. Huijser. 2022. Reduced speed limit is ineffective for mitigating the effects of roads on ungulates. Conservation Science and Practice 4(3):e618. https://doi.org/10.1111/csp2.618
T. Rytwinski, K. Soanes, J. A. G. Jaeger, L. Fahrig, C. S. Findlay, J. Houlahan, R. van der Ree, and E. A. van der Grift. 2016. How effective is road mitigation at reducing road-kill? A meta-analysis. PLOS ONE 11(11): e0166941. https://doi.org/10.1371/journal.pone.0166941
Schoenecker, K. A., Esmaeili, S., & King, S. R. B. (2023). Seasonal resource selection and movement ecology of free-ranging horses in the western United States. The Journal of Wildlife Management, 87(2), e22341. https://doi.org/10.1002/jwmg.22341
Shilling, F. M., & Waetjen, D. P. (2015). Wildlife-vehicle collision hotspots at US highway extents: Scale and data source effects. Nature Conservation, 11, 41–60. https://doi.org/10.3897/natureconservation.11.4438
Sullivan, T. L., Williams, A. F., Messmer, T. A., Hellinga, L. A., & Kyrychenko, S. Y. (2004). Effectiveness of temporary warning signs in reducing deer-vehicle collisions during mule deer migrations. Wildlife Society Bulletin, 32(3), 907–915.
Oscar Sweigart, “Three horses struck, two fatally within weeks on Assateague Island,” WBOC, 14 August 2026.
Walburn Viviano, M. (2021, July 11). Assateague pony killed, foal injured by hit & run driver. Chesapeake Bay Magazine/Bay Bulletin.
Maps to download
Indicate the location of any horse/car interactions with an X and email merry@equusferus.com or DM through our Facebook page. Please include (if known) the horse’s name, date, and time of day. Right-click the image, select “Save image as,” and save it to your hard drive. If you have trouble, we can email you a copy.
The End
