What is an ESAL? ESAL Formula Where: Typical Load Equivalency Factors (LEFs) (based on AASHTO & typical LEFs) Vehicle Type Axles Typical Load (kips per axle) Approx. ESAL per Pass Passenger Car (sedan) 2 2–3 0.0004 Pickup / SUV 2 3–4 0.001 Delivery Van (2-axle, light) 2 4–5 0.005 Single-Unit Truck (2-axle, 6-tire) 2 6–9 […]
Traffic signals are at the heart of modern intersections. Their timing not only dictates how efficiently traffic flows but also affects safety, pedestrian accessibility, and overall network performance. To design or evaluate a signal plan, engineers rely on a set of technical terms that describe how green, yellow, and red indications are distributed across phases
Public transit systems are the backbone of urban mobility—moving millions of people daily, reducing congestion, and supporting economic activity. Yet, many agencies around the world struggle with financial sustainability. Farebox revenue alone rarely covers operating costs, and capital-intensive expansions demand alternative funding sources. To thrive, transit agencies must diversify their income streams beyond fares. This
A transportation (travel demand) model is a quantitative framework that forecasts how people and goods move through a region under different land-use and network scenarios. Done well, a model becomes a decision engine: it helps test road and transit projects, pricing policies, and growth plans before spending real money. This guide covers when you actually
Sight distance is one of the most important considerations in road design. It represents the length of roadway visible to a driver, ensuring there is enough distance to perceive, react, and stop safely when encountering obstacles or conflicts. Inadequate sight distance can lead to unsafe conditions, higher crash risks, and poor traffic flow. This reference
Designing a parking lot requires attention to efficiency, safety, and accessibility. Below is a reference guide with parking space dimensions, aisle widths, clearances, layout types, and line-marking standards that designers can use when planning surface or structured parking facilities. Try our parking layout calculator to see how many space you need. Standard Parking Space Dimensions
Transportation planning and engineering is one of the most dynamic and impactful career paths available today. It sits at the intersection of technology, infrastructure, sustainability, and public policy. If you’ve ever searched “Should I study transportation engineering?” or “Is traffic engineering a good career?”, this guide will help you understand why the answer is a
If you already work with trip generation, you know the headline challenge in many Traffic Impact Studies (TIS/TIA): not all site trips are “new” to the network. Some are simply siphoned from vehicles already passing by. Getting this right can change turn lane warrants, signal timing, and mitigation costs. This guide is a practitioner’s deep-dive
A Transportation Master Plan (TMP) is a comprehensive, long-term strategic document that guides the development, management, and investment in a community’s transportation system. It ensures that transportation networks, roads, public transit, walking, cycling, and freight are planned in a coordinated way to meet current needs while accommodating future growth. TMPs are typically prepared for cities,
Choosing the right type of public transit vehicle is a balance between passenger demand, operating cost, capacity, and corridor constraints. From standard 12 m buses to high-capacity metro trains, each vehicle type has unique strengths and limitations. Planners often start by estimating peak-hour ridership and matching it to the seating and standing capacity of available
