This guest article was written by Matt Zajack, who we previously profiled for his work on a traffic counting device. This story was edited by Adrienne So.
The River View Cemetery (RVC) route is a high-traffic, though fragile, de facto public connector that happens to run through private property. For decades, Portlanders on bikes have relied on the goodwill of cemetery officials to provide a critical transportation link between Sellwood and SW Terwilliger Blvd (the alternatives are much too busy, or else closed to cycling).
Last year’s closures underscored the urgency to find a safe, public, all-weather alternative, but supporting data has been hard to come by. Portland’s Bureau of Transportation (PBOT) has been asked to deploy traffic counters, but has been unable to do so. We also suspected that a few hours of counting would not be able to capture the necessary data to show who is using the RVC and when. My company, Green Dormer Solutions, partnered with Lewis & Clark College to provide a pro bono, data-driven analysis of the route’s usage with the Traffic Monitor device to provide both cyclists and city planners with evidence to justify the creation of a safe, public route.
Please Don’t Speed
We collected data over a 36-day period, split between summer (August 15-28, 2025) and autumn (September 19-October 10, 2025), at the Macadam entrance gate. Bicyclists accounted for the largest volume of users, with no meaningful statistical difference between weekdays and weekends—the RVC is used for both commuting and recreation.
Significantly, the data showed that significantly more bicycles were recorded entering (uphill) the cemetery than exiting (201 vs. 103). This strong directional trend suggests the cemetery route is a preferred, safer path for the challenging climb to the Southwest Portland neighborhoods, as alternatives like Taylor’s Ferry Road are perceived as dangerous. 79 percent of group rides (clusters of at least 5 bicycles) also travel uphill, which solidifies the need for a safe alternative to the SW Portland climb.
Other key findings included:
- RVC is a cut-through route for commuters. While bicycle volume was evenly distributed after 8 am, with a slight bump from 4-6 pm on weekdays, motorized vehicle volume was concentrated during the evening commute. This indicates that car drivers are using RVC as a cut-through route.
- Speed makes the RVC a high-risk environment. The speed limit in RVC is 15 mph, but 66 percent of autos and 15 percent of bicycles were captured moving over this limit. The speeding auto cut-through traffic creates a high-risk environment on private roads that were never designed for this volume and speed.
- The alternative is worse. The primary public alternative, Taylor’s Ferry Road, has an Average Daily Traffic (ADT) of over 5,560 westbound autos with an 85th percentile speed of 49 mph (posted 35 mph limit). The data confirms the high volume of bicycle traffic relies on RVC precisely due to the unsafe nature of alternatives.
Avoiding the Uphills
The RVC serves a critical function, primarily because the public alternative is a challenging and dangerous route. S Taylors Ferry Rd, is an uphill/eastbound slog, with an 85th percentile speed of 44 mph (in a 35 mph zone) and high Average Daily Traffic (ADT) counts of over 6,000. Overall, there were significantly more bicycles entering the cemetery (going uphill) versus exiting (going downhill) at a ratio of 201 to 103 bicycles ADT.
The opposite trend was observed for cars and pedestrians, with more exiting (downhill) than entering, indicating that drivers see the cemetery as a viable link for downhill travel as high-speed cut-through to avoid potential congestion on Taylor’s Ferry or Macadam. This also creates more potential conflict, as daily pedestrian count is slightly higher than cars, at 90 vs 88 ADT. All user activity increases during the evening commute time.
The most alarming discovery relates to speed. The speed limit within River View Cemetery is 15 mph. The data shows that cars are routinely exceeding this limit. 66% of automobiles were captured moving over 15 mph (the speed limit), compared to just 15% of bicycles, and this speed differential is magnified when traveling downhill: 74% of cars vs. 39% of bicycles were over 15 mph.
This confirms that the cemetery’s roads are being treated as a high-speed, non-residential street by most drivers, directly contrasting with the intended quiet nature of a cemetery and the safety needs of active transportation users. The risks are compounded by the presence of vulnerable road users and the narrow, winding nature of the roads.
Furthermore, our seasonal and time-of-day analysis showed that autos were significantly faster in autumn than in summer, with more cars driving 20-30 mph. This increase in speed is a dangerous trend that increases risk for all users as the days get shorter and weather worsens.
Shedding Light on Group Rides
We also looked at group cycling, which has been a point of contention for cemetery users. Group rides were defined as at least five bicycles clustered within 10 seconds and had no way of differentiating recreational or commuter rides.
While group rides might be controversial, they make up 8 percent of total daily bicycle volume. Weekday morning commuter group rides are largely uphill and are likely the result of a “platoon effect”, caused by the traffic light at Macadam.
A Note on Scalable Traffic Monitoring
City agencies often face capacity constraints. Traffic counters take time and money and would not be able to showcase the rich data captured here. The TrafficMonitor.ai device highlights how communities and advocates can gather the robust data they need to spur action.
The Alternative Route Crisis
The precarious nature of the cemetery access was recently thrust into the spotlight with temporary closures due to construction, prompting a familiar outcry from the community. But RVC is the only safe option. The data provided by the analysis confirms that the alternatives are significantly longer, steeper grades, and often unsafe.
The most direct alternative, S Taylors Ferry Rd, is not a designated bicycle route. It is a high-speed, high-traffic environment where the only way to feel safe descending is to take the lane at a speed nearing traffic. The fact that the 85th percentile speed on Taylors Ferry is 49 mph westbound and 44 mph eastbound—far exceeding the 35 mph posted limit—makes it a dangerous prospect for most cyclists.
The predicament presented by the roadway data—high-speed motor vehicles, peak commuter traffic, and the ever-present threat of closure—deserves immediate and concrete action. While the discussion is often complicated by debates over private property, tax exemption, and the sanctity of cemeteries, the core issue remains: There is no safe, public, guaranteed, and direct connection for active transit and non-vehicular users between the Sellwood Bridge area and SW Portland.
The comprehensive traffic and speed data, focused on holistic roadway data— not just car-centric numbers, and collected over a six-week period— is crucial for informing stakeholders, which includes Lewis & Clark College, River View Cemetery, and Portland City Council District 4 representatives.
Methodology
The data was collected at the cemetery entrance gate near the Sellwood Bridge, using a trafficmonitor.ai device—an open-source smart city traffic monitoring solution utilizing edge machine learning object detection and Doppler radar. This data collection study was estimated at less than $1,000 to implement. Comparable private counting and speed analysis on a multi-modal route often costs upwards of $29,000.
The trafficmonitor.ai system prioritizes privacy. The device uses local object detection inferencing and Doppler radar, not capturing or storing identifying visuals (no images, license plates, or faces). It only records the object class (bicycle, automobiles, pedestrian), times, speed, and direction for fully local data de-identification. This ensures ethical, granular, and holistic data collection on traffic patterns for urban planning, without compromising user identity or personal information.
Data Definitions
| Category | Timeframe | Duration |
|---|---|---|
| Summer | Aug 15-28, 2025 | 14 days |
| Autumn | Sep 19-Oct 10, 2025 | 22 days |
Object detection labels and classification:
AI Transparency disclosure: This analysis utilized the public domain Coral SSDLite MobileDet based on the public domain COCO dataset with the following labels:
- Bicycle: combined ebikes, bikes
- Vehicle: combined cars, trucks, motorcycles
- Pedestrian: person (minus) bicycle (may include scooters and non-bicycle micro-mobility)