Peak Misinformation

Project Connect’s staff and consultants recommended against using Bus Rapid Transit (BRT) in large part because of its inability to meet peak time needs as the Austin of 2030 and beyond keeps growing. However, upon closer inspection, BRT seems to have plenty of capacity to meet system needs.

Here are the key PowerPoint slides presented to CCAG (The Mayor’s advisory group) explaining BRT’s disqualification. Let’s examine them closely.

brt_slide_22

Above is Slide 22. Two important things to note here. First, the vehicle capacity for BRT. The 85 number is reasonable, but by no means the upper limit. The MetroRapid fleet right here in Austin has 100 passenger capacity vehicles. Maybe the turns would be too tough, but that hasn’t been spelled out in any materials. In general, tires turn tighter than rails, so it seems the 100 passenger vehicles should be fine. More importantly, pay attention to that 950 inter-stop peak. It’s unclear where exactly it comes from, since the Project Connect methodology remains hidden, but let’s just accept it for now.

brt_slide_24

In Slide 24, PCS asserts that to meet the 950 inter-stop peak load, there need to be 15 vehicles (of the 85 passenger variety). Wait, but that would be a capacity of 1,275, you say? Shouldn’t it just be 12 vehicles to meet that peak need? Well, PC staff believes that running 12 vehicles an hour – resulting in a 5 minute wait time or “headway” – would alter the “service profile”. In simpler terms, while the original model predicted a 950 peak at a 10 minute wait time, meeting that need requires such frequent service that some existing riders will bunch up to ride closer to that peak time; other on-the-fence commuters will decide they want to use BRT. Either way, the peak changes as a result of the frequency. It doesn’t seem to have any significant impact on overall ridership though – we are talking about 300 people shifting around. The 2030 daily boardings number asserted by PC is around 17,000.

So far, the impact of this is the need to move around or maybe even add a few vehicles at rush hour. But somehow, this slight kink becomes completely disqualifying to BRT on Slide 25.

brt_slide_25

This slide asserts that the minimum headway for “reliable service” is 3 minutes. For folks new to transit jargon, “reliable service” means that a person can just walk to a stop or station and know that they won’t be waiting long before getting on their way. Operationally, that’s a vehicle running every 3 minutes or 20 per hour.

Now look at the red lines in the green bars. That’s the previously discussed inter-stop peak. For BRT, the author of the slide has kept the higher, frequency-induced peak. But for rail, the inter-stop peak is still just the original 1,100 from Slide 22. It seems to me that if you had rail coming along every 3 minutes (compared to the baseline 10 minute profile), there would be some change in the inter-stop peak, not to mention ridership.  This presentation seems to overestimate rail’s available capacity.

All of this leads to the Slide 25’s most important and misleading assertion – that BRT provides “no capacity” for system expansion. If we look at the chart itself, at 20 buses per hour there are 1,700 seats available. Hence, 25% of capacity is left over. I am not sure how 25% became 0%. Moreover, if you use 100-seat buses, then the reliable service requirement uses 64% of capacity. 36% is definitely not 0%.

MetroRapid will end up costing under $50 million to get started. While it is not BRT, the amount gives a sense of the magnitude of capital costs for a BRT fleet and basic infrastructure like stop benches. That’s way less that $1.4 billion. Project Connect estimates that the weekday ridership for Grove-to-Highland rail will be 18,000 in 2030. And for BRT in 2030? 17,000.

If system expansion is really the central issue disqualifying BRT, a billion dollars seems like an awful lot of money to pay to really, really, really make sure to avoid standing-room-only BRT buses on Grove-Highland sometime in 2040 or 2050.

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