Benchmarking 'Flow': Qualitative Measures for Evaluating Cyclist and Pedestrian Priority at Complex Intersections

At a complex intersection, the difference between a street that works for everyone and one that frustrates cyclists and pedestrians often comes down to a single, slippery concept: flow. Flow is not just speed — it's the sense of being expected, of moving without constant stops or conflicts, of having your time valued as much as a driver's. But how do you benchmark something so subjective? This guide offers a qualitative framework for evaluating cyclist and pedestrian priority at complex intersections, using observable cues and design principles rather than expensive data collection. We'll walk through eight key dimensions that any planner, advocate, or engineer can apply during a site visit or plan review.

Who Needs to Benchmark Flow — and Why Now?

If you're reading this, you've likely stood at an intersection and felt that something was off. Maybe the bike lane disappears at the crossing, or pedestrians have to wait through two full signal cycles to cross a slip lane. The people who most need a flow benchmark are transportation planners reviewing design proposals, city council members evaluating street projects, and community advocates pushing for safer crossings. The urgency comes from a shift in standards: many cities are adopting Vision Zero or Complete Streets policies that promise priority for active modes, but the actual designs often fall short. Without a clear way to measure priority, it's easy to approve a design that looks good on paper but fails in practice.

We've seen this play out in dozens of projects. A city installs a protected bike lane, but at the major intersection, the bike signal is timed so poorly that cyclists end up running the red or weaving onto the sidewalk. Pedestrians get a leading interval, but it's so short that only the fastest walkers clear the crosswalk before turning cars encroach. These are flow failures. Benchmarking flow means catching these issues before they become habits. It's about asking: does this intersection treat walking and biking as legitimate modes, or as afterthoughts? The answer shapes everything from signal timing to curb radius to crossing island placement.

We'll focus on qualitative measures because they're accessible. You don't need a license plate survey or a microsimulation model. You need a checklist, a stopwatch, and a willingness to watch how people actually move. This approach is especially useful for smaller agencies or advocacy groups that lack research budgets but still want to hold projects accountable.

The Option Landscape: Three Approaches to Measuring Priority

There is no single official method for benchmarking cyclist and pedestrian flow, but practitioners tend to cluster around three approaches. Each has strengths and blind spots, and understanding them helps you choose the right tool for your context.

Approach 1: The Level of Traffic Stress (LTS) Framework

Originally developed for bicycle networks, LTS classifies segments and intersections into four stress levels based on speed, volume, and infrastructure. For pedestrians, a similar framework uses crossing distance, signal timing, and refuge islands. The strength of LTS is its simplicity: you can rate an intersection in minutes. The weakness is that it's static — it doesn't capture how flow changes across a day or how user behavior adapts. A low-stress intersection on paper can still have poor flow if signals are poorly timed or if drivers don't yield.

Approach 2: The Multimodal Level of Service (MMLOS) Method

MMLOS, promoted by the Highway Capacity Manual, attempts to quantify delay and comfort for each mode using formulas. For pedestrians, it considers crossing delay, sidewalk width, and perceived safety. For cyclists, it looks at bike lane type, intersection crossing treatments, and motor vehicle speeds. The advantage is that it produces a numeric score that can be compared across projects. The downside is that it requires detailed data — volume counts, signal timings, geometry — and it can miss the subtle, qualitative aspects of flow, like whether a bike box actually feels safe to use or whether pedestrians feel rushed.

Approach 3: The Observational Audit (Our Recommended Starting Point)

This is the approach we'll focus on. It's a structured but flexible method where you visit the intersection during peak and off-peak times, watch for specific behaviors, and note design cues. You don't need a formula — you need a checklist. Key indicators include: the number of cyclists who dismount and walk their bikes (a sign of poor bike flow), the number of pedestrians who start crossing during the walk signal but finish after the flashing don't walk (a sign of inadequate clearance time), and the number of near-misses or conflicts between turning cars and people crossing. This method is grounded in what you can see and hear: do people look relaxed or tense? Are they waiting patiently or taking risks? The observational audit is low-cost, easy to explain to stakeholders, and directly tied to user experience.

Most teams we've worked with start with the observational audit, then use LTS or MMLOS to quantify specific issues. The three approaches are complementary, but for benchmarking flow, the observational audit gives you the richest qualitative data.

Comparison Criteria: What to Look for When You Watch

When you're standing at an intersection, what should you actually look for? We've distilled six criteria that capture the essence of flow for cyclists and pedestrians. These aren't exhaustive, but they cover the most common failure points.

1. Delay and Wait Time

How long do people wait to cross? For pedestrians, a wait of more than 30 seconds at a signalized crossing is associated with increased non-compliance — people start crossing against the light. For cyclists, delay at intersections is often the biggest deterrent to using bike lanes. Watch for queue lengths at bike signals and note if cyclists have to wait through multiple cycles.

2. Clearance Time and Crossing Distance

Do pedestrians have enough time to cross comfortably? The standard walking speed used in design is 3.5 feet per second, but many older adults and children walk slower. If the crossing distance is long and the clearance time is tight, flow suffers. For cyclists, look at whether the bike signal provides enough time to clear the intersection before conflicting movements begin.

3. Conflict Points and Weaving

How many potential conflicts exist between cyclists, pedestrians, and turning vehicles? A well-designed intersection minimizes conflict points by using protected phases, raised crossings, or offset crosswalks. Watch for areas where people have to weave — for example, a right-turn lane that cuts across the bike lane or a bus stop that forces cyclists to merge with traffic.

4. Visibility and Expectation

Can everyone see each other? Poor visibility leads to hesitation and near-misses. Look for sight lines blocked by parked cars, vegetation, or infrastructure. Also assess whether the design signals what is expected: clear markings, obvious crossing locations, and intuitive signal phases. If people look confused, flow breaks down.

5. Perceived Safety vs. Actual Safety

Sometimes an intersection is statistically safe but feels dangerous — for example, a wide, straight crossing with no refuge island. People may avoid it or take risks. Conversely, a design that feels safe may encourage more walking and biking. Flow is as much about perception as about crash rates. Watch for signs of discomfort: people looking over their shoulders, hesitating, or stepping off the curb early.

6. Universal Accessibility

Flow must work for everyone, including people using wheelchairs, pushing strollers, or with visual impairments. Check for curb ramps that align with crosswalks, tactile warning strips, and audible pedestrian signals. A design that forces a detour or a long wait for a person using a mobility aid is a flow failure.

Trade-Offs in the Design Choices That Affect Flow

Every design choice involves a trade-off. Understanding these trade-offs helps you benchmark flow honestly — you can't have everything, but you can prioritize what matters most for your context.

The key is to match the design to the context. A high-volume, high-speed arterial may need a fully separated cycle track and LPI to achieve good flow, while a low-speed neighborhood street might work fine with shared lane markings and a simple crosswalk. Benchmarking flow means recognizing that a design that works in one place may fail in another.

Implementation Path: How to Conduct a Flow Audit

Ready to benchmark an intersection? Here's a step-by-step process that we've used in real projects. It takes about an hour per intersection, plus travel time.

Step 1: Prepare Your Checklist

Before you go, print or load a checklist that includes the six criteria above. Leave space for notes and sketches. If you're auditing multiple intersections, standardize the form so you can compare results.

Step 2: Choose Your Time Slots

Visit during peak (morning and evening commute) and off-peak (midday or weekend). Flow can change dramatically. For example, a crossing that works fine at noon may be a nightmare at 5 PM when turning traffic is heavy.

Step 3: Observe for 15 Minutes Per Mode

Spend 15 minutes watching pedestrians, then 15 watching cyclists. Count how many people wait, how long they wait, and how they cross. Note any conflicts or near-misses. Use a stopwatch to time crossing durations for a sample of users.

Step 4: Document Design Details

Take photos of the intersection from all approaches. Note the presence and condition of bike lanes, crosswalks, signals, curb ramps, and refuge islands. Measure crossing distances if you can do so safely (or estimate using known lane widths).

Step 5: Talk to Users (Optional but Valuable)

If time allows, briefly interview a few pedestrians and cyclists. Ask: 'How often do you use this crossing? What would make it better? Do you feel safe here?' Their answers often reveal issues you might miss.

Step 6: Score Each Criterion

Use a simple scale: 1 (poor flow) to 5 (excellent flow). Be honest — if you saw people running to cross, that's a 1 or 2. If everyone crossed calmly and without conflict, that's a 4 or 5. Average the scores for an overall flow rating.

Step 7: Identify Priority Improvements

Based on your scores, list the top three improvements that would most improve flow. For example, if clearance time is low, a longer pedestrian signal phase might be the fix. If conflict points are high, consider a protected turn phase or a raised crossing.

Risks of Skipping the Qualitative Benchmark

What happens if you don't benchmark flow? The most common risk is that you design an intersection that meets engineering standards but fails real people. A classic example is the intersection with a bike lane that ends at a right-turn only lane, forcing cyclists to merge into traffic or dismount. The design may comply with state guidelines, but flow is terrible. People stop using the bike lane, or they take risks.

Another risk is that you prioritize one mode at the expense of another. For example, a signal timing plan that gives cyclists a long green may leave pedestrians with a short crossing time, leading to non-compliance. Without qualitative benchmarking, you might not notice until complaints roll in. The cost of retrofitting after construction is much higher than catching issues during design review.

There's also a political risk. If you champion a project that claims to prioritize active modes but the actual experience is poor, you lose credibility with the community. People remember the intersection where they felt unsafe or delayed. Benchmarking flow before construction gives you evidence to push for changes — and to defend the project if it works.

Finally, ignoring flow can lead to equity problems. Intersections in lower-income neighborhoods often have wider roads, faster speeds, and fewer crossing improvements. Without a qualitative check, these disparities persist. Benchmarking flow with an equity lens — asking who benefits and who is left out — can help redirect resources to where they're needed most.

Frequently Asked Questions About Measuring Flow

How many intersections should I audit to get a useful picture?

For a corridor-level assessment, we recommend auditing at least three intersections: one at each end and one in the middle. For a network-wide assessment, choose a representative sample based on traffic volume, land use, and intersection type. Even a single audit can reveal important issues, but multiple audits give you a sense of patterns.

Can I use a smartphone app to help with timing?

Yes, any stopwatch app works. There are also apps designed for pedestrian and cyclist level of service, but we find that a simple timer and a notebook are just as effective for qualitative work. The key is consistency — use the same method at each intersection.

What if I'm not a transportation professional? Can I still do this?

Absolutely. The observational audit is designed to be accessible. You don't need a degree in traffic engineering to notice that people look scared or that the walk signal is too short. Community advocates have used similar methods to push for changes in their neighborhoods. That said, for official project evaluation, you may need to coordinate with the local agency to ensure your findings are taken seriously.

How do I handle intersections with very high traffic volumes?

High-volume intersections can be intimidating to observe. Stay on the sidewalk or on a refuge island if available. Never stand in the roadway. If the intersection is too chaotic to observe safely, consider using video recording (with permission) and reviewing the footage later. Many cities have traffic cameras you can request access to.

What's the single most important thing to look for?

If you only have time to check one thing, look at the turning conflict between right-turning cars and pedestrians crossing the side street. This is where most failures occur. If the pedestrian signal is green while a right-turn arrow is also green, watch for near-misses. If you see drivers yielding inconsistently, that's a clear sign of poor flow.

Putting the Benchmark to Work: Next Steps for Your Project

Benchmarking flow is not an end in itself — it's a tool to make better decisions. Here are three specific next moves after you complete your audit.

First, share your findings with the people who can act on them. If you're an advocate, bring your audit results to a city council meeting or a transportation department open house. Use photos and simple scores to make your case. If you're a planner, use the audit to inform design changes before the 90% review stage — it's much easier to shift a crosswalk or adjust signal timing early in the process.

Second, combine your qualitative data with existing quantitative data. Look at crash reports for the intersection — do they align with your observations? If you saw near-misses between right-turning cars and pedestrians, check if there are reported crashes of that type. This triangulation strengthens your argument.

Third, repeat the audit after improvements are made. The only way to know if your changes worked is to go back and observe again. Did the new LPI reduce conflicts? Did the bike box actually get used? Post-implementation audits are rare but incredibly valuable. They build a body of evidence for what works in your community.

Flow is not a luxury — it's a measure of whether a street respects the people who use it. By benchmarking it qualitatively, you give yourself a clear, communicable way to demand better. Start with one intersection. The rest will follow.