[{"_1":2,"_111":-5,"_112":-5},"loaderData",{"_3":4,"_26":27},"root",{"_5":6,"_17":10,"_18":19,"_20":21,"_22":10,"_23":-5,"_24":-5,"_25":10},"user",{"_7":8,"_9":10,"_11":10,"_12":-5,"_13":-5,"_14":15,"_16":-5},"roles",[],"isAuthenticated",false,"isPremium","planName","subscriptionStatus","featureFlags",{},"insightsBudget","isDevelopmentHost","userPreferences",{},"recaptchaSiteKey","6LcvOJcUAAAAAHsB-gPGfGktcRlKpH7OTIU_dMTD","isImpersonating","impersonation","affiliateStatus","isFreedomPortal","routes/v2/article/layout",{"_28":29,"_30":31},"notFound",true,"relatedArticles",[32,76,87,99],{"_33":34,"_35":36,"_37":38,"_39":40,"_41":42,"_43":44,"_45":46,"_47":48,"_49":50,"_51":52,"_53":54,"_55":56,"_57":58,"_59":60,"_61":62,"_63":64,"_65":66,"_67":68,"_69":70,"_71":72,"_73":74,"_75":74},"mediaId",6133675,"mediaKeyId","5698878-5b37c87b2742c61d11fc82657ab45325","parentId",5698878,"title","Recent safety research highlights: intelligent speed assistance, truck visibility and AI‑data use","audioSeconds",123,"startMs",3721000,"endMs",3844000,"viewUrl","/Search/View?dp=1&key=5698878-5b37c87b2742c61d11fc82657ab45325&start=3721&end=3844","thumbnailUrl","https://assets.pipeline.soar.com/5698878-5b37c87b2742c61d11fc82657ab45325/thumbnail_3721000.jpg","articleUrl","/articles/6133675/Colorado/Recent-safety-research-highlights-intelligent-speed-assistance-truck-visibility-and-AIdata-use","mediaUrl","https://secure.pipeline.soar.com/6133675-4c9a60e821de4944cd8f347133cda9b1/orig.mp4?Expires=1775117504&Signature=KRnUmp2SjFLNbutPdynTSh8XucdihzHATu5IXN3KQch3kJhn05YqZb08rGx-FVS4uFvKg5Kp6nG39lGywBdstF6xhji9YreeMPYtQGrD8NSpOz43NiUjPaF92dNsXBDmrN48bUXHv-rYaZC1iY8DnFPSNDS~riSpN2e23gemd9y7O3TfL4r~VnyVSMQ4kG5L~G1bnaTokF5N8dxCQS9gMCbI0K2kaU~OyqlfEm-hY-VOPTA4Z1khlFXRbLdwkIcj4mX6LmsSRa~wDnBizchpLu6x9SMeb7nsvec8Wx1wx14C2PnyuK~WMscTb8QC4IuNoIonCxuyVnF0A7Ew7p7Kjw__&Key-Pair-Id=KUT5TJCACFTXG","author","Denver Regional Council of Governments","date","2025-08-27T17:43:36Z","article","Catherine (staff member) summarized several recent safety reports and webinars for practitioners. She highlighted three areas of interest: intelligent speed assistance (ISA), vehicle and truck design for pedestrian visibility, and leveraging AI/big‑data tools for safety analysis.

On intelligent speed assistance, Catherine said the technology — aftermarket or built‑in systems that limit vehicle speed — has been effective at reducing severe speeding and is being used in some jurisdictions and by courts as a condition for repeat offenders. She cautioned that adoption pathways vary by state and may involve legislative or court processes.

On large‑truck visibility, Catherine referenced analysis by a research center that used simulation and testing of truck cab designs and concluded that many large trucks have limited forward visibility and that some configurations can prevent drivers from seeing children or adults in crosswalks. The recommended approaches include adopting high‑vision truck cabs for public fleets, installing side guards, and “rightsizing” vehicles where appropriate.

On AI and big‑data, Catherine summarized a recent NCHRP report that described when vehicle‑based or camera‑based data can be useful (inventory, near‑miss analyses and systemwide trend spotting) and warned of noise and quality issues — for example, smartphone data can be less reliable than vehicle‑based sources and surveillance camera outputs require tested algorithms. She recommended that agencies define performance measures before purchasing products and consider the trade‑offs for intersection‑level analysis versus system‑wide trends.

These summaries were informational; no policy actions followed directly from the webinar.","mediaType","Video","parentTitle","DRCOG | Regional Vision Zero Working Group June 10, 2025","oneSentenceSummary","Speakers summarized recent findings: intelligent speed assistance (ISA) can reduce high‑risk speeding, truck cab design affects pedestrian visibility, and AI/big‑data tools can help safety analysis but have limits.","taxTitle","Denver Regional Council of Governments, Governor's Boards and Commissions, Organizations, Executive, Colorado","taxId",27825,"location","Colorado","headline","","shortSummary",{"_33":77,"_35":36,"_37":38,"_39":78,"_41":79,"_43":80,"_45":80,"_47":81,"_49":82,"_51":83,"_53":84,"_55":56,"_57":58,"_59":85,"_61":62,"_63":64,"_65":86,"_67":68,"_69":70,"_71":72,"_73":74,"_75":74},6133680,"Region secures $15 million in SSB projects; crash dashboard and quick‑build toolkit updates planned",0,3688000,"/Search/View?dp=1&key=5698878-5b37c87b2742c61d11fc82657ab45325&start=3688&end=3688","https://assets.pipeline.soar.com/5698878-5b37c87b2742c61d11fc82657ab45325/thumbnail_3688000.jpg","/articles/6133680/Colorado/Region-secures-15-million-in-SSB-projects-crash-dashboard-and-quickbuild-toolkit-updates-planned","https://secure.pipeline.soar.com/6133680-be06d5c9461aeb6bf81909b1f8133dca/orig.mp4?Expires=1775117504&Signature=OUURe8~S2DMicfMb2AJqoUQF1y1pdhJUwNGKEljkkX9r9TXiDOzAXMXaWMOeOMsGD4HUeJUTf0sv4T0fncUk-KiaLPMqaTV2sykxd-8Z-TqEOGfqNNkrM0d6eRHgj5bdQlA70-e2eqrH~Igmimnen6za-QCH-4IMYIyIroy1Hb0ysxFKttsbMBEoLhdEqnRW-0iNGh9LzQRDnVF220x0dhMEwqCa~Xxbxsh1SdeZwIDdIDk0Lb5URZaAMBm0MmrtzdaQW919h4WzX-BHVeffHLa286p3oSzNp8b0KmEzvqRj4ukpaK67XsgJZ8rE1F~iIbNrVZ4V6eG5Zkhrar3Q3Q__&Key-Pair-Id=KUT5TJCACFTXG","Catherine (staff member) updated attendees on regional program work and tools. She said this year’s regional SSB application is titled \"Safer streets, improving pedestrian and left turn safety in the Denver region,\" includes eight projects across eight jurisdictions and totals about $15,000,000 in proposed improvements. She thanked jurisdictions that submitted letters of interest and said staff plan to coordinate earlier for future calls for projects.

Byron Schulte (senior GIS specialist, DRCOG) gave a brief update on the crash data dashboard. Byron said the dashboard launched in September and that DRCOG will request 2024 crash data from CDOT and issue a short survey to stakeholders to collect feedback for a September rollout of an updated dashboard covering 2020–2024. He noted trade‑offs with longer time ranges (slower dashboards) but said including additional years is technically possible and the team will consider it based on user needs.

Catherine also asked for volunteers for a quick‑build toolkit focus group to help shape a regional toolkit (five to ten volunteers, one to two meetings). The toolkit would provide short‑term, low‑cost implementation guidance and could be an educational resource for staff and the public.

No votes or funding decisions were made during the webinar; Catherine said slides and materials will be shared after accessibility remediation and that staff will follow up with volunteers and interested agencies.

Attendees were reminded the group meets every other month and the next scheduled meeting is Aug. 12.","Meeting organizers said this year’s Safe Streets and Roads for All (SSB) regional submission includes eight projects totaling about $15 million; staff also announced an upcoming crash‑data dashboard refresh and called for volunteers for a quick‑build toolkit focus group.",{"_33":88,"_35":36,"_37":38,"_39":89,"_41":90,"_43":91,"_45":92,"_47":93,"_49":94,"_51":95,"_53":96,"_55":56,"_57":58,"_59":97,"_61":62,"_63":64,"_65":98,"_67":68,"_69":70,"_71":72,"_73":74,"_75":74},6133685,"Cities report mixed practices on flashing yellow arrow signage and protected left timing",125,2016000,2141000,"/Search/View?dp=1&key=5698878-5b37c87b2742c61d11fc82657ab45325&start=2016&end=2141","https://assets.pipeline.soar.com/5698878-5b37c87b2742c61d11fc82657ab45325/thumbnail_2016000.jpg","/articles/6133685/Colorado/Cities-report-mixed-practices-on-flashing-yellow-arrow-signage-and-protected-left-timing","https://secure.pipeline.soar.com/6133685-3a6d8a71224f7d2b6704628c43f23f6a/orig.mp4?Expires=1775117504&Signature=KVWT1xwr8K-n10wGy0Hhxz7R~WD4c4K9vAV82CKfUSF3ubjmDBVksZry9z5lvgpwryFZ~NjQLhmXBUvXwpoA2SwZyVApW7Qk1mQMwZ2itN8VztlK9T7KaXvm3UyVg2e6-SkFFjBgU2wVra-AOn72e8rpwbNijrueYaB02M58x84tcTHi5~UC7l5O50B8YUtn7Iy7~XgL61qdEFac-FWDzzFksZBB8lSajRHEGda8IFPhKeHg5XrFXQljTWVBlag0oPNXEvSwCELdj6tW8SQauIXfk8geX~4Xnhne81eLJmDd95SEEwkXOvGqEVL-6fS0JOhxXxQXY8zlmElVKIXEiA__&Key-Pair-Id=KUT5TJCACFTXG","During a local government panel, Anna Buntz (city traffic engineer, City of Centennial) and Kelly Dune (transportation engineering manager, City of Lakewood) described practical approaches to left‑turn phasing and signage. Both cities use the same engineering criteria recommended in CDOT's guidance (crash history, cross‑product, sight distance, lane counts and speed), but neither has a formally adopted public policy flowchart; both said decisions are made case‑by‑case and used internally as guidance.

On flashing yellow arrows and the R10‑12 signage prescribed in the MUTCD, Kelly Dune said Lakewood does not post the R10‑12 sign and avoids adding extra mast‑arm signs to prevent conflict with the signal display. Anna Buntz said Centennial generally does not use the sign on new installations and that past outreach showed the public tends to “increase their hesitation and not go” when worded signs caused confusion. Anna added that Centennial’s newer installations include pedestrian‑presence inhibits so that if a pedestrian pushes a button the left turn display can omit the flashing yellow arrow and provide protected time.

Panelists emphasized local constraints: legacy signal equipment, equipment retrofits, and staffing/prioritization limits. Kelly said Lakewood treats offset dual lefts and negative offsets conservatively, using protected‑only phasing 24/7 at locations with negative offsets or multiple approach lanes where visibility is impaired. Both cities noted close collaboration with police crash investigators; Kelly said police‑reported scene details sometimes prompt signal reviews even with fewer than five crashes at a location.

No policy votes were taken. Panelists recommended a documented internal decision framework to improve consistency while preserving engineering judgment and operational flexibility.","Panelists from Centennial and Lakewood said they apply CDOT‑style criteria case‑by‑case; Lakewood and Centennial generally do not post additional R10‑12 signage with flashing yellow arrows and rely on signal indications and public outreach.",{"_33":100,"_35":36,"_37":38,"_39":101,"_41":102,"_43":103,"_45":104,"_47":105,"_49":106,"_51":107,"_53":108,"_55":56,"_57":58,"_59":109,"_61":62,"_63":64,"_65":110,"_67":68,"_69":70,"_71":72,"_73":74,"_75":74},6133690,"Regional safety presenters urge clearer guidance on left‑turn signal phasing to cut severe crashes",438,128000,566000,"/Search/View?dp=1&key=5698878-5b37c87b2742c61d11fc82657ab45325&start=128&end=566","https://assets.pipeline.soar.com/5698878-5b37c87b2742c61d11fc82657ab45325/thumbnail_128000.jpg","/articles/6133690/Colorado/Regional-safety-presenters-urge-clearer-guidance-on-leftturn-signal-phasing-to-cut-severe-crashes","https://secure.pipeline.soar.com/6133690-bffaee4f095e1511e9fc612028c7f07a/orig.mp4?Expires=1775117504&Signature=PFwGGPU6JFnV9lUsX6SnK0ILAjgnvD45XLv94b~dur-WqMlcbkIcv8J2dKMlq0DXQPz1XwYZkbDHArDD-yWJ-rAoIbnTOxBZozbYaet0pd4Y2wZS1yET1QaAc2Y25tuQv1DQf6s78acEIuR5vv8oPJMqiIiNwuGn5cdQ~AEPHIM~BbCB35N5y3xeOHriyZo~jfF8xuoOlLrPdmnYCHS-7xbhFbz9HfjWXbbGQk1lTOzrbHozJPif8KaNpLWdll8YSswgsqexhoCC33217zbcHbZFZd4ZIW6NwwQj1Lej7xotWc9exhhDtSUB6y43uvrrSJGakXl0JPuqlF2eBDKcTg__&Key-Pair-Id=KUT5TJCACFTXG","Catherine (staff member) opened the webinar by saying left turns at signalized intersections are a persistent contributor to severe crashes in the Denver region and urged local agencies to consider clearer decision rules. “11 of all fatal and severe crashes in the Denver region involve a vehicle making a left turn at a signalized intersection,” she said. Presenters from the consulting firm Consort described work they completed for CDOT to turn an earlier memo into a more detailed guidance flowchart that local regions can use when evaluating left‑turn phasing.

The guidance packages a two‑stage flowchart. Diana McHale (Consort) and George Shackle (Consort) said the first stage applies to nearly every intersection and checks safety and geometric criteria — sight distance, speed limits, lane configuration and pedestrian/cyclist interactions — to indicate whether an intersection should be considered for protected‑only phasing. The second stage addresses existing signalized intersections and adds operational criteria such as cross‑product crash calculations and delay thresholds that can point toward protected‑permissive timing.

Consultants summarized empirical findings cited in the guidance: moving an intersection from permissive‑only to protected‑permissive yields measurable crash reductions, and the literature generally shows that protected‑only or leading protected left phasing produces lower left‑turn crash rates than permissive or protected‑permissive operations. Diana McHale noted limits in the research base: “there’s really only one research study that was rigorous enough to develop a crash modification factor,” and she said more large‑sample research is needed for firm crash‑modification factors.

Presenters explained trade‑offs. Protected‑only phasing provides the greatest reduction in severe left‑turn and pedestrian conflicts but often increases vehicle delay and can reduce signal progression for through traffic. Protected‑permissive phasing offers a compromise but can be problematic at some geometries (for example, non‑offset double left lanes). The guidance flags situations where agencies should default to protected‑only, including intersections with constrained sight distance that cannot be corrected, certain opposing speed thresholds, or specific bicycle/pedestrian crossing conditions where a left turn would cross a bidirectional bike facility.

CDOT staff described current use of the guidance. David (CDOT staff) said CDOT distributed the guidance to regions, has supported Region 1 and Region 3 assessments under task orders, and is running more detailed left‑turn studies that combine the flowchart approach with additional datasets (for example, ATS PM and DiAxis crash outlier screening).

Panelists from local governments described how they apply criteria in practice. Anna Buntz (city traffic engineer, City of Centennial) and Kelly Dune (transportation engineering manager, City of Lakewood) said neither city has a formally adopted flowchart but that both apply similar criteria case‑by‑case: crash history, cross‑product calculations, speed and sight‑distance conditions, lane counts and offsets. Kelly said Lakewood has converted many intersections to flashing yellow arrow operation and reported “a 67% reduction in left turn crashes” after switching some locations and implementing lagging left operations; she added some locations still require protected only phasing due to geometry (for example, offset dual lefts).

The presenters and local staff recommended that jurisdictions document decision criteria — at least as internal guidance — to ensure consistent choices, while preserving engineering judgment. Diana McHale said the CDOT flowchart is not a formal statewide policy but “to provide regions with some clear guidance on how to evaluate and adjust their left turn phasing.”

The webinar closed with practical notes for agencies: (1) use time‑of‑day protected phasing where crash or pedestrian exposure is concentrated in parts of the day; (2) require additional operational review before switching phasing (adjusting green splits, coordination plans and evaluating delay); and (3) where data are sparse, use conservative safety checks (sight distance, opposing speed) to default toward protection.

Agencies and consultants agreed on one operational recommendation that is often low cost: convert green ball left indications to flashing yellow arrows systemically and evaluate installation of leading pedestrian intervals and other pedestrian protections as part of a safe‑systems approach.

No formal vote or policy adoption occurred during the webinar; presenters offered to share the flowchart and supporting slides and to support regional studies on request.","Presenters reviewed Colorado Department of Transportation guidance and a new CDOT‑commissioned flowchart for deciding when to move permissive left turns to protected permissive or protected‑only phasing, emphasizing safety trade‑offs and the need for local policies.","actionData","errors"]

Article not found

Recent safety research highlights: intelligent speed assistance, truck visibility and AI‑data use

Region secures $15 million in SSB projects; crash dashboard and quick‑build toolkit updates planned

Cities report mixed practices on flashing yellow arrow signage and protected left timing

Regional safety presenters urge clearer guidance on left‑turn signal phasing to cut severe crashes