Context: Road mitigation to reduce animal–vehicle collisions (AVCs) is usually based on analysis of road survey animal carcass data. This is used to identify road sections with high AVC clusters. Large mammals that are struck and die away from a road are not recorded nor considered in these analyses, reducing our understanding of the number of AVCs and the cost–benefit of road mitigation measures.

Aims: Our aim was to develop a method to calculate a correction factor for large mammal carcass data reported through road survey. This will improve our understanding of the magnitude and cost of AVCs.

Method: Citizen scientists reported animal carcasses on walking surveys along transects parallel to the highway and reported observations using a smartphone application at three sites over a 5-year period. These data were compared with traditional road survey data.

Key result: We found that many large mammals involved in AVCs die away from the road and are, therefore, not reported in traditional road surveys. A correction factor of 2.8 for our region can be applied to road survey data to account for injury bias error in road survey carcass data.

Conclusions: For large mammals, AVCs based on road survey carcass data are underestimates. To improve information about AVCs where little is known, we recommend conducting similar research to identify a correction factor to conventionally collected road survey carcass data.

Implications: Identifying road mitigation sites by transportation agencies tends to focus on road sections with above-threshold AVC numbers and where cost–benefit analyses deem mitigation necessary. A correction factor improves AVC estimate accuracy, improving the identification of sites appropriate for mitigation, and, ultimately, benefitting people and wildlife by reducing risks of AVCs.

背景：缓解道路交通事故以减少动物与车辆碰撞（AVC）通常是基于对道路调查动物尸体数据的分析。这用于识别具有高AVC群集的路段。在这些分析中，没有记录也没有考虑被撞死并远离道路的大型哺乳动物，这减少了我们对AVC数量和减少道路措施成本效益的了解。

目的：我们的目的是开发一种方法来计算通过道路调查报告的大型哺乳动物mammal体数据的校正因子。这将增进我们对AVC的数量和成本的了解。

方法：公民科学家在沿着与高速公路平行的样带的步行调查中报告了动物尸体，并报告了使用智能手机应用程序在5年内在三个地点进行观察的情况。这些数据与传统的道路调查数据进行了比较。

关键结果：我们发现，许多参与AVC的大型哺乳动物死于道路之外，因此传统道路调查中未对此进行报告。可以将我们地区的校正系数2.8应用于道路测量数据，以解决道路测量胎体数据中的伤害偏差误差。

结论：对于大型哺乳动物，基于道路调查car体数据的AVC被低估了。为了在鲜为人知的情况下改善有关AVC的信息，我们建议进行类似的研究，以找出常规收集的道路勘测car体数据的校正因子。

含义：交通运输机构确定道路缓解地点倾向于将重点放在具有高于阈值AVC值的路段上，并且在需要进行成本效益分析的地方。校正因子可提高AVC估算的准确性，改善对适合减灾地点的识别，并最终通过降低AVC的风险使人类和野生生物受益。