Don’t speed or drive after drinking, avoid looking at phones, and pull over to rest when fatigued

On average, for every 1% increase in speed, the chance of a fatal crash rises by roughly 4%. There is no safe blood alcohol level for driving. Manipulating a mobile phone while driving makes a crash roughly 3.6 times more likely than attentive driving, and dialing increases it by 12.2 times. When a driver is visibly fatigued, crash risk increases by roughly 3.4 times.

There’s no direct cost. Driving a bit slower adds just a few minutes to each trip. The hard part is drinking less at social gatherings and resisting the urge to check notifications. On long road trips, stop and rest for at least 20 minutes every 4 hours.

According to the World Health Organization (WHO), a 1% rise in average vehicle speed produces a 4% increase in fatal crash risk. Crash risk begins elevating even at very low blood alcohol concentrations. WHO also reports that drivers using mobile phones are approximately 4 times more likely to crash than those who do not, and hands-free sets offer little safety advantage. A naturalistic driving study using in-vehicle video cameras in over 3,500 vehicles analyzed 905 injury and property-damage crashes compared against baseline alert, attentive, sober driving: overall handheld cell phone manipulation increased crash odds by 3.6 times (odds ratio [OR] 3.6). Dialing increased risk by 12.2 times, texting/messaging by 6.1 times, reaching for the device by 4.8 times, browsing by 2.7 times, and handheld conversing by 2.2 times. Drivers exhibiting observable fatigue and drowsiness had a 3.4-fold increase in crash risk (OR 3.4).

The 1% speed and 4% fatality ratio derives from traffic modeling rather than clinical randomized trials. For alcohol and driving, WHO indicates an upward exponential trend without a fixed harmless threshold. Odds ratios for cell phone distraction and drowsiness evaluate all-cause injury and property-damage crashes rather than fatal crashes specifically; baseline comparisons used ideal attentive driving conditions, slightly elevating relative ratios compared to everyday driving averages. Traffic laws prohibit handheld calls while driving (carrying fines and demerit points); while hands-free calls are legally permissible, WHO notes they do not significantly reduce cognitive distraction. Driving continuously for more than 4 hours without at least a 20-minute break is a statutory violation. If drowsy, pull over into a service station immediately to rest. Sedating medications like chlorpheniramine or diphenhydramine also induce marked driving impairment, as noted in Chapter 34, Rule 12. Persistent driving drowsiness combined with loud snoring warrants sleep apnea evaluation, detailed in Chapter 3, Rule 27.

WHO (2025). Road traffic injuries fact sheet：「Drivers using mobile phones are approximately 4 times more likely to be involved in a crash than drivers not using a mobile phone.」「Hands-free phones are not much safer than hand-held phone sets.」https://www.who.int/news-room/fact-sheets/detail/road-traffic-injuries ; Dingus TA 等 (2016). Driver crash risk factors and prevalence evaluation using naturalistic driving data. PNAS 113(10):2636-2641. https://doi.org/10.1073/pnas.1513271113 ; 中华人民共和国道路交通安全法（2021 年修正）第二十二条第二款：「过度疲劳影响安全驾驶的，不得驾驶机动车」；第九十条：「处警告或者二十元以上二百元以下罚款」. https://flk.npc.gov.cn/detail?id=ff8081817ab231eb017abd617ef70519 ; 中华人民共和国道路交通安全法实施条例（2017 年修订）第六十二条：驾驶机动车不得有「（三）拨打接听手持电话、观看电视等妨碍安全驾驶的行为」「（七）连续驾驶机动车超过4小时未停车休息或者停车休息时间少于20分钟」. https://flk.npc.gov.cn/detail?id=ff8080816f3cbb3c016f40f566c10e23 ; 公安部 (2021). 道路交通安全违法行为记分管理办法（公安部令第 163 号）第十一条：一次记 3 分的有「（六）驾驶机动车有拨打、接听手持电话等妨碍安全驾驶的行为的」「（十四）连续驾驶载货汽车超过4小时未停车休息或者停车休息时间少于20分钟的」；第九条：一次记 9 分的有「（七）连续驾驶中型以上载客汽车、危险物品运输车辆超过4小时未停车休息或者停车休息时间少于20分钟的」. http://www.gov.cn/gongbao/content/2022/content_5679697.htm