AASHTO

Articles, guides, and products tagged "AASHTO" — a combined view of every catalogue resource on this topic.

User guide

Defensive riding in mixed motor traffic: lane positioning, primary vs secondary position, door zone, right hook + left cross at the intersection, SMIDSY / look-but-failed-to-see — how to avoid conflicts with cars

Unlike braking technique, cornering, or night riding, a separate safety layer is the **strategy of interacting with motor traffic**: where to position yourself in the lane, how to read drivers before an intersection, where the door zone sits, what right hook and left cross are, and why statistically the **intersection** — not the straight section — is the more dangerous segment (NACTO: >40% of urban bike fatalities in 2022 happened at intersections; UK DfT 2022: e-scooter casualty rate is three times higher than for pedal cycles). This guide transfers to the e-scooter the classic principles of vehicular cycling (John Forester, *Effective Cycling* 1976, MIT Press 7th ed. 2012), Smart Cycling of the League of American Bicyclists, the NACTO Urban Bikeway Design Guide 3rd ed. 2025, the AASHTO Guide for the Development of Bicycle Facilities, ROSPA UK road-safety guidance, IIHS, and AAA Foundation research. Covers: lane-positioning theory (primary vs secondary position; why 'as far right as possible' is the worst strategy); door zone (12-27% of urban bike collisions — Wikipedia; Dutch Reach countermeasure); right hook (a turning vehicle crosses the bike lane), left cross (an oncoming driver turns across your path); SMIDSY / look-but-failed-to-see as a perceptual phenomenon (Hurt Report 1981 motorcycle baseline, 75% of motorcycle crashes involve a passenger car, 66% are ROW violations); 5 active-signalling rules (positioning + eye-contact + speed-modulation + escape-path + worst-case escape); why a bike lane is not always safer than the road; how to ride with the flow (vehicular) vs in a facility (segregated); a 30-minute practice drill.

13 min read

User guide

Emergency maneuvers and obstacle avoidance on an e-scooter: swerving, threshold braking, two-step weight transfer, target fixation, and PIEV reaction time

Emergency maneuvering is a discipline distinct from planned braking and from steady-state cornering. There is no time for a second attempt — there is one decision made in 0.5–1.5 seconds and one motor sequence executed in the next 0.3–0.8 seconds. If the decision is wrong (you brake when you should have swerved, or you swerve when you should have stopped), two-wheeled physics with small wheels and a high center of gravity punishes you immediately: 86 million shared trips on e-scooters in 2019 ([NACTO — Shared Micromobility in 2019](https://nacto.org/wp-content/uploads/2020/08/2019sharedmicromobilityreport_final.pdf)) generate 118,485 ED visits in 2024 ([CPSC — E-Scooter and E-Bike Injuries Soar, 2024](https://www.cpsc.gov/Newsroom/News-Releases/2024/E-Scooter-and-E-Bike-Injuries-Soar-2022-Injuries-Increased-Nearly-21)), and CPSC explicitly notes that e-scooters have much higher centers of gravity and smaller wheels with less shock absorption, so pavement quality matters significantly more than it does for bikes or e-bikes. Small wheels and a tall CoG mean that the same patch of damaged pavement that a cyclist will absorb as a transient ride-quality blip will throw an e-scooter rider over the handlebars. This guide covers the two symmetric skills the Motorcycle Safety Foundation (MSF) calls core emergency skills: **threshold braking** (maximum deceleration at the edge of wheel lockup) and **emergency swerve** (rapid line change without braking during the lean phase). Plus — when to use which, and when to combine them sequentially. ENG-first sources: MSF Basic RiderCourse / 'Do I Brake or Swerve' / Quick Video Tips, Wikipedia (Countersteering, Threshold braking, Dooring), CyclingSavvy (Emergency Maneuvers, Door Zone Tragedy), Cycle World and MCrider (target fixation), AASHTO (2.5 s PIEV), CPSC injury reports, IIHS sidewalk speed studies, Nature Communications (projected time-to-collision e-scooter), ScienceDirect (e-scooter vs bicycle crash typology), 99% Invisible (Dutch Reach), Bennetts (brake and swerve), Hupy and URide (emergency drill protocols).

14 min read

User guide

Riding on difficult road surfaces on an e-scooter: contact-patch physics on cobblestones, tram tracks, gravel, wet leaves, painted lines and expansion joints

Six disciplinary micro-environments that no existing guide covers individually: cobblestones (Belgian setts, granite slabs, round river-rock cobbles — 5–30 Hz vibration, micro-loss-of-contact, μ_wet 0.3–0.4, sweet-spot speed, line between joints); tram tracks (wheel-slot 35–45 mm wide × 38–58 mm deep for standard 1435 mm gauge, crossing angle ≥45° mandatory, convex rail head, wet-rail μ 0.05–0.10 — worse than ice, four failure modes); gravel and sand (two-layer dynamics, front-wheel plowing effect, amplified slip-angle in cornering); wet leaves (μ ~0.1 as on ice); painted lines (μ_wet ↓ ×3 to 0.2–0.3, metal manhole covers and plates even worse); expansion joints and poor patch repairs (parallel-grooves like miniature rails, step-transitions deflecting the front wheel, sunken utility covers 2–5 cm below grade). The common denominator is the 5–15 cm² contact patch on an e-scooter tire and the three types of its failure: material μ failure, geometric trap-or-deflect, kinetic momentary contact loss from vibration. Defensive cross-cut: tire-pressure adjustment 30–35 PSI vs 40–45, active stance with soft knees and elbows for 2–3 cm of vertical absorption, weight bias (rear over bumps, forward over slick patches), 60–75 % of normal speed, rear-brake-first on slippery surfaces. Especially relevant for Ukrainian cities with cobblestoned historical centres (Lviv, Kyiv-Podil, Kamianets-Podilskyi) and tram networks (Kyiv, Lviv, Kharkiv, Dnipro, Odesa, Mariupol). ENG-first sources: Edinburgh/Vienna/Toronto tram-track cyclist injury studies, AASHTO/TRB pavement marking BPN friction standards, Paris-Roubaix vibration analysis (cycling-physics engineering refs), wheel-rail interface μ literature, Schwalbe/Vittoria tire pressure technical guides, ASCE bridge expansion joint design, OSM surface= + smoothness= tag refs, League of American Bicyclists wet-leaves safety briefings.

14 min read