# Colorado Study Tests Cannabis Driving Effects in Adults 65 and Older > **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637) > **Publisher:** CED Clinic (https://cedclinic.com) > **Canonical URL:** https://cedclinic.com/colorado-older-adults-cannabis-driving-study/ > **Published:** 2026-08-12T12:17:18-04:00 | **Last Modified / Clinically Audited:** 2026-09-28T13:58:46-04:00 > **Clinical Summary:** A Colorado older adults cannabis driving study is testing simulated driving after inhaled cannabis. Results and a safe waiting interval are not established. --- CED Clinical Relevance #81 Protocol Watch Rocky Mountain PBS reported on an active Colorado School of [Public Health](https://cedclinic.com/cannabis-mold-contamination-risks-recall-safety/) study addressing a practical safety question for older adults who use cannabis. The university study page confirms the investigators, eligibility, procedures, and observational design. The study has no results yet, so its value is the clinically relevant question and the gap it is designed to address. Clinical Insight | CED Clinic Researchers at the Colorado School of [Public Health](https://cedclinic.com/cannabis-mold-contamination-risks-recall-safety/) are studying how inhaled cannabis affects simulated driving and cognitive performance in adults ages 65 and older. Rocky Mountain PBS reported on August 12, 2026, that the team is about halfway through a 12-month data-collection period and hopes to share results within two years. The university’s study page confirms that participants attend up to three visits, provide urine and blood samples, complete thinking and memory tests, and use a driving simulator before and after using their own cannabis. This is an observational, within-person study, not a randomized clinical trial and not a report of results. It cannot yet tell patients how long to wait before driving. Its importance is that older adults are often excluded from cannabis-driving experiments even though age-related changes, health conditions, medications, product choice, and frequency of use could affect impairment. The practical advice remains simple: do not drive while impaired, do not use a future study as permission to guess at a safe interval, and discuss [cannabis use](https://cedclinic.com/cannabis-cardiovascular-health-insights-2024/) alongside other medications that can affect alertness or coordination. Older AdultsCannabis and DrivingProtocol WatchPublic SafetyClinical Counseling Audience Older adults who use cannabis, families and caregivers, clinicians who counsel older patients, and readers interested in cannabis-related [driving safety](https://cedclinic.com/cannabis-cognitive-aging-older-adults-march-2026/). Primary Topic An active Colorado observational study examining cannabis, simulated driving, and cognitive performance in adults ages 65 and older. Source [Read the full source](https://www.rmpbs.org/news/science-environment/colorado-cannabis-driving-research-older-adults) Colorado researchers are testing how older adults perform on a driving simulator before and after using their own cannabis. The study addresses an important evidence gap, but it is still collecting data and has not established a safe waiting period for driving. What This Study Teaches Us This report shows why older adults need to be included directly in cannabis-driving research. It also shows the difference between a worthwhile study question and an answer that is ready for clinical use. Why This Matters Older adults may use cannabis while also managing age-related changes, chronic conditions, and medications that affect attention, balance, reaction time, or alertness. Clinicians need evidence that reflects this population, while patients need clear advice that does not outrun the data. Study Snapshot News report Rocky Mountain PBS, August 12, 2026 Research team Colorado School of [Public Health](https://cedclinic.com/cannabis-mold-contamination-risks-recall-safety/) investigators Carolyn DiGuiseppi, PhD, MD, MPH, and Ashley Brooks-Russell, PhD, MPH Population Adults ages 65 to 89 who use cannabis and currently drive Design Observational, within-person comparison using self-provided cannabis Procedures Up to three visits, surveys, biological samples, cognitive testing, and simulated driving Route studied Participants smoke or vape cannabis they purchased themselves Current stage Roughly halfway through a 12-month data-collection period, according to Rocky Mountain PBS Results Not yet available Expected reporting Investigators hope to share results within about two years What it cannot answer today A safe post-use waiting interval for driving Clinical Bottom Line The Colorado study asks a useful, overdue question about cannabis and driving in older adults. Until results are available and independently evaluated, it should not change anyone’s decision to avoid driving while impaired. What Happened Rocky Mountain PBS reported that Colorado researchers are recruiting and testing adults 65 and older to examine how [cannabis use](https://cedclinic.com/cannabis-cardiovascular-health-insights-2024/) affects simulated driving and cognitive performance. Participants complete testing when sober and after using cannabis they obtained themselves. The Colorado School of Public Health study page independently confirms the investigators and procedures. The project includes surveys, urine and breath testing, blood draws, thinking and memory assessments, and a driving simulator. For Patients and Families This study does not provide a new rule for how many hours an older adult should wait before driving. It is still collecting data, and individual impairment can be influenced by dose, THC concentration, route, prior exposure, sleep, alcohol, other drugs, and prescription medications. If cannabis causes sleepiness, slowed thinking, dizziness, altered perception, or poor coordination, do not drive. Families can help by planning transportation before use rather than trying to judge impairment afterward. For Clinicians The report supports asking older patients about cannabis in the same medication-safety conversation as sedatives, sleep aids, opioids, antihistamines, and alcohol. The clinically useful question is not only whether a patient uses cannabis, but also product type, route, dose, frequency, timing, co-use, and whether driving follows use. Counseling should remain individualized and conservative because this study has not reported outcomes and a simulator cannot capture every demand of real-world driving. How This Fits the Bigger Picture Older adults are increasingly represented among people who use cannabis, yet research samples often exclude them because of medical conditions or medications. That exclusion makes it harder to translate findings from younger adults into safe counseling for older patients. A prior peer-reviewed cohort study of 31 regular cannabis users ages 65 to 79 found more lane weaving and lower speed 30 minutes after smoking, with subjective effects persisting longer. That small study offers context, but it does not predetermine the Colorado project’s findings or establish a universal waiting period. Key Clinical Caveats The Colorado project studies smoked or vaped, self-selected products. Its eventual results may not generalize to edibles, beverages, tinctures, or standardized medicines, which can have different onset and duration profiles. The study is observational. Product potency, dose, tolerance, medications, and health status may differ across participants. Simulator performance is informative but is not identical to collision risk on public roads. Policy and Public Health Angle Driving policy needs measures that relate to functional impairment, not assumptions based only on age or a positive cannabis test. The study may eventually help refine that discussion, but it is too early to claim that it validates any legal threshold or enforcement tool. Public messaging should avoid both extremes: [cannabis use](https://cedclinic.com/cannabis-cardiovascular-health-insights-2024/) should not be treated as proof of current impairment, and legal or [medical access](https://cedclinic.com/topic-legalization-info/) should not be treated as proof that driving after use is safe. How Strong Is This Evidence? The active study is confirmed by a direct university research page, and Rocky Mountain PBS interviewed the investigators and observed a participant using the simulator. The supporting literature includes peer-reviewed observational studies of older drivers. The current news value is therefore well supported, but the Colorado project itself has not produced outcome data. Where This Paper Deserves Skepticism The strongest reason for skepticism is timing. This is a report about research in progress, and the investigators are only about halfway through data collection. Recruitment materials and investigator comments explain purpose and methods, but they cannot establish results. The study uses self-provided products and simulated driving, which improves real-world relevance in some respects while increasing variability and limiting direct claims about crash risk. What This Paper Does Not Show The report does not show that older adults are uniquely impaired by cannabis, that cannabis caused any reported Colorado traffic death, or that a particular number of hours makes driving safe. It does not establish a blood THC threshold, compare every route of administration, or account for every medication and health condition relevant to older adults. It also does not report treatment benefits or risks for any medical condition. How This Fits With the Broader Clinical Conversation Cannabis-driving research has repeatedly struggled to translate product exposure or blood THC into a simple measure of functional impairment. Age adds another layer because metabolism, cognition, vision, mobility, and medication burden vary widely among older adults. The useful public-health contribution of this project will depend on its completed sample, transparent methods, effect estimates, uncertainty, and peer-reviewed reporting. Until then, the study should be understood as evidence being gathered, not evidence already settled. Dr. Caplan’s Take *I am glad to see older adults included directly in this work. Patients in this age group are not simply older versions of younger study participants. Medication burden, balance, vision, sleep, and cognitive reserve can all shape the safety conversation.* *The practical message today is not complicated: this study has not produced a safe waiting-time rule. Patients should plan not to drive after using cannabis when impairment is possible, and clinicians should ask about timing, route, dose, other substances, and the patient’s actual transportation plan.* What a Careful Reader Should Take Away A new Colorado study is examining a real evidence gap, but it has no results yet. Older adults who use cannabis should continue to avoid driving when impairment is possible and should review medication interactions and transportation planning with a clinician. Evidence Interpretation Guide Table of Contents - [How to Read News About a Cannabis Study That Is Still Underway](#How_to_Read_News_About_a_Cannabis_Study_That_Is_Still_Underway)[Four questions for careful readers](#Four_questions_for_careful_readers) - [The Same Study Can Mean Different Things Depending on the Question Being Asked](#The_Same_Study_Can_Mean_Different_Things_Depending_on_the_Question_Being_Asked)[Do Not Turn a Study Announcement Into a Waiting-Time Rule](#Do_Not_Turn_a_Study_Announcement_Into_a_Waiting-Time_Rule) - [Ask About the Whole Exposure Context](#Ask_About_the_Whole_Exposure_Context) - [Methods Are Not Outcomes](#Methods_Are_Not_Outcomes) - [Make Transportation the Easy Choice](#Make_Transportation_the_Easy_Choice) - [Naturalistic Products Improve Relevance and Add Variability](#Naturalistic_Products_Improve_Relevance_and_Add_Variability) - [Functional Evidence Matters More Than Assumptions](#Functional_Evidence_Matters_More_Than_Assumptions) - [Older Adults Belong in Safety Research](#Older_Adults_Belong_in_Safety_Research) - [The Results and Their Limits Matter Next](#The_Results_and_Their_Limits_Matter_Next) - [Frequently Asked Questions](#Frequently_Asked_Questions)[Related](#Related) ## How to Read News About a Cannabis Study That Is Still Underway Research-in-progress stories can be valuable when they identify an important unanswered question. They become misleading when the question is written as though researchers have already found the answer. This Colorado project deserves attention because it directly includes older adults and measures driving-related performance. Its conclusions must wait for completed data and peer review. ### Four questions for careful readers **Are results available?**No. The team is still collecting data and expects reporting on a longer timeline. **What is actually being measured?**Simulated driving, thinking and memory performance, biological samples, and participant-reported information before and after self-provided inhaled cannabis. **Who is represented?**The study targets adults ages 65 to 89 who use cannabis and drive, subject to health and eligibility requirements. **What would make the findings useful?**Transparent reporting of the sample, products, timing, outcomes, uncertainty, medication context, and limits of simulator-to-road translation. The Research Question How does acute inhaled cannabis use affect driving-related and cognitive performance in adults 65 and older, and do age, baseline cognition, or use frequency modify those effects? The Patient Question How long after my own cannabis product can I safely drive, given my health and medications? The Bottom Line The study may inform the research question later. It does not answer the individual patient’s question today. CED Perspective Lens ## The Same Study Can Mean Different Things Depending on the Question Being Asked Scientific papers rarely answer a single question. Patients, clinicians, researchers, policymakers, and critics often read the same data differently. The perspectives below explore how this study looks through several evidence-based lenses. Lens Overview The study has different implications for patients, clinicians, families, researchers, policymakers, and readers evaluating safety claims. #### Do Not Turn a Study Announcement Into a Waiting-Time Rule The study has no results yet, and it examines inhaled products rather than every cannabis route. Plan transportation before use and avoid driving whenever impairment is possible. Lens takeaway No new safe-driving interval has been established. #### Ask About the Whole Exposure Context Route, dose, THC concentration, frequency, timing, alcohol, and sedating medications all matter to counseling. Document the patient’s driving demands and transportation plan, not just cannabis use status. Lens takeaway Counseling should connect product use to function and driving plans. #### Methods Are Not Outcomes Investigator interviews and recruitment pages can verify what a study intends to do, but not what it will find. Wait for completed, peer-reviewed results before accepting claims about magnitude, duration, or subgroup differences. Lens takeaway The evidence gap is real, and it remains open. #### Make Transportation the Easy Choice Families can reduce risk by arranging rides before cannabis use rather than debating impairment afterward. Concerns about confusion, falls, medication interactions, or unsafe driving deserve a calm clinical conversation. Lens takeaway Advance planning is more reliable than post-use judgment. #### Naturalistic Products Improve Relevance and Add Variability Allowing participants to use their own products reflects real behavior more closely than a single standardized dose. It also makes dose, potency, and product differences important analytical challenges. Lens takeaway Real-world relevance and experimental control must be balanced. #### Functional Evidence Matters More Than Assumptions Policy should distinguish recent use, measurable impairment, and residual detectability. This project may add evidence later, but it cannot validate a legal threshold before results exist. Lens takeaway Do not use an unfinished study to justify a policy conclusion. #### Older Adults Belong in Safety Research Excluding medically complex older adults can leave the population most in need of counseling without directly applicable evidence. Future studies will still need to address routes beyond smoking and vaping and the effects of common medication combinations. Lens takeaway Representative evidence is essential for useful guidance. #### The Results and Their Limits Matter Next Watch for final enrollment, product characteristics, timing of testing, effect estimates, subgroup analyses, and peer-reviewed publication. The most important follow-up will be whether observed simulator changes translate into clinically useful counseling without false precision. Lens takeaway The next meaningful milestone is completed, reviewable data. Join the Conversation Have a question about how this applies to your situation? [Ask Dr. Caplan](https://benjamincaplan.com/ask-dr-caplan) Want to discuss this topic with other patients and caregivers? [Join the forum discussion](https://cedclinic.com/interact/discussion-forums/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Physician-Led, Whole-Person Care A doctor who takes the time to truly understand you. Personal care that starts with listening and is guided by experience and ingenuity. Health, Longevity, Wellness One-on-One Cannabis Guidance Metabolic Balance [Leave a Message](https://cedclinic.com/contact/) [Metabolic Care](https://cedclinic.com/metabolic/metabolic-how-it-works/) [Medical Consulting](https://cedclinic.com/book/) [Cannabis Care](https://cedclinic.com/book/) [https://cedclinic.com/contact/](https://cedclinic.com/contact/) Share this Evidence Watch [X](https://twitter.com/intent/tweet?text=Colorado+Study+Tests+Cannabis+Driving+Effects+in+Adults+65+and+Older&url=https%3A%2F%2Fcedclinic.com%2Fcolorado-older-adults-cannabis-driving-study%2F) [LinkedIn](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fcedclinic.com%2Fcolorado-older-adults-cannabis-driving-study%2F) [BlueSky](https://bsky.app/intent/compose?text=Colorado+Study+Tests+Cannabis+Driving+Effects+in+Adults+65+and+Older%20https%3A%2F%2Fcedclinic.com%2Fcolorado-older-adults-cannabis-driving-study%2F) [Instagram](https://www.instagram.com/drcaplan/) [Substack](https://doctorapprovedcannabis.substack.com/) [RSS](https://cedclinic.com/feed/) Source: [Older adults are getting high and driving for science, Rocky Mountain PBS](https://www.rmpbs.org/news/science-environment/colorado-cannabis-driving-research-older-adults) Related Reading at CED Clinic Continue exploring the evidence [Hidden Driving Danger When Edible Cannabis and Alcohol Mix](https://cedclinic.com/hidden-driving-danger-when-edible-cannabis-and-alcohol-mix-sciencedaily/) Earlier CED coverage of driving-related impairment when [cannabis and alcohol](https://cedclinic.com/can-you-mix-weed-and-alcohol/) are combined. [Read the driving safety context](https://cedclinic.com/hidden-driving-danger-when-edible-cannabis-and-alcohol-mix-sciencedaily/) [Research Uncovers Motivations Behind Older Adults’ Use of Cannabis Edibles](https://cedclinic.com/research-uncovers-motivations-behind-older-adults-use-of-cannabis-edibles/) Context on why older adults use cannabis and why route-specific counseling matters. [Explore older-adult use patterns](https://cedclinic.com/research-uncovers-motivations-behind-older-adults-use-of-cannabis-edibles/) [FAA Reviews Cannabis Fitness-for-Duty Rules](https://cedclinic.com/faa-cannabis-rescheduling-pilot-fitness-for-duty-review/) A policy-focused look at impairment evidence and safety-sensitive occupational rules. [Compare the policy question](https://cedclinic.com/faa-cannabis-rescheduling-pilot-fitness-for-duty-review/) ## Frequently Asked Questions What is the Colorado older-adult cannabis driving study? It is an observational Colorado School of Public Health study measuring simulated driving and cognitive performance in adults ages 65 to 89 before and after they use their own inhaled cannabis. Has the study reported results? No. Rocky Mountain PBS reported that the team is roughly halfway through a 12-month data-collection period and hopes to share results within about two years. Does the study establish how long to wait before driving? No. It has not reported results and does not provide a validated waiting-time rule for any individual or product. What kind of cannabis do participants use? Participants smoke or vape cannabis they obtained themselves, making the exposure naturalistic but variable in product, potency, and dose. Why focus on adults 65 and older? Older adults are often excluded from cannabis-driving experiments even though age-related changes, health conditions, and medications may affect impairment and counseling needs. Is a driving simulator the same as real-road driving? No. A simulator can measure standardized driving behaviors without putting the public at risk, but it cannot reproduce every condition or consequence of driving on public roads. Can a blood THC level prove driving impairment? A blood THC result does not by itself provide a simple, universally reliable measure of functional impairment. Timing, use pattern, product, and individual factors complicate interpretation. What should older patients discuss with clinicians? Discuss route, dose, THC concentration, timing, frequency, other medications or substances, dizziness or sedation, and plans for transportation after use. What should patients do until results are available? Avoid driving whenever cannabis-related impairment is possible, plan transportation before use, and do not rely on an unvalidated waiting interval. What evidence should careful readers look for next? Look for completed enrollment, transparent product and timing data, effect estimates with uncertainty, medication context, limitations, and peer-reviewed publication. ### Related --- ### Verification & Medical Governance - **Lead Clinical Author:** Benjamin Caplan, MD - **Credentials:** Board Certified in Family Medicine (ABFM), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House). - **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`). - **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/). - **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637). - **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).