Why Your “Just Three Minutes” Request Makes Transit Planners Twitchy

Source: YotzStudios.com

“Oh, but it’s only adds on another three minutes,” is one of those phrases I’ve heard over and over again during my time as a transit planner and scheduler.  And like some evil Pavlovian trigger, I can’t help but get bad flashback twitches every time I hear it.

The changes that folks request that “will only take three minutes” sound so small and harmless.  But the truth is that the time it would take you to soft boil an egg is all it takes to overcook a transit system and turn its reliability, ridership and costs into a rubbery mess.

But YOU might not know that.  And so when transit planner me says “no” or “meh” to what seems like a pretty simple AWESOME request from you, I am going to seem like a (twitchy flashbacking) unhelpful negative jerk.

In an effort to enable us all to understand each other better–and, uh, apparently for me to work through some repressed issues–here are some of the trade-offs and rationale behind the most common “oh, it only needs another three minutes” requests from passengers, transit staff and local governments.

The Most Common Transit “Three Minute Asks” and Their Trade Offs

From what I’ve seen, the most common requests of this nature involve seemingly small changes to routes, connections and road networks.  Here’s the skinny on each:

Classic Three Minute Ask #1: “The bus route already runs nearby, so why can’t it go THERE, too?”

Old Family Circus comics should typically never be used as a guide for transit route planning best practices… (Comic author: Bil Keane)

In this one, existing or potential passengers ask for an established route to be extended to cover more territory or serve an additional destination. The time required for this extension is almost always estimated by the requester as taking “just two or three more minutes.”

• Why it seems to make so much sense – For sure, this one seems logical and I can certainly understand why people ask.  The bus is already somewhat in the neighbourhood, so why not bring it closer to Aunt Joe or those teenage kids or the Total Monster Grocery Emporium on the other side of the tracks?  More people would use transit if it only came a little closer, right?
• The challenging trade off – The crux of this one (as my scheduling colleague Robert Madison used to frequently point out), is that it pits the time of people not yet on the bus against those already on board. What he meant by this is that any change to transit routing aimed at bringing a bus closer to theoretical potential customers needs to weigh its benefits and impacts against how much longer the ride is going to seem to the actual existing customers already on board.
• The bottom line – Yes, sometimes extending a route does make sense if it’s to a major new destination.  However, just understand that if a route extension is going to turn the majority of a trip’s passengers into “time hostages” in order to go past a point that very few of them will ever use, a “just three minute” route diversion degrades the overall quality of service.
  • It will make the transit trip slower, less direct and overall less convenient.  A change that stands to lose more existing passengers than it gains in new ones is not worth it.

Classic Three Minute Ask #2: “Can’t you schedule the buses to wait so that I can always make my connection?”

In this one, the request is to have a transit agency hold buses at a transfer point to make a connection.  Most often this is from bus to bus or from train to bus within a transit system.  Sometimes this is also between transportation modes, such as from a connecting ferry, plane or intercity bus.

• Why it seems to make so much sense – We’ve all been there: the elation that comes when you make a dicey connection: Whoo hoo!  And the defeated agony that sets in when you race out the back door of one bus or come rocketing up the subway escalator only to see the tail lights of your connecting ride fade into the distance.  Argghhh!!!
  • No one likes that “just missed” feeling.  This request arises from the thought it would be super if every bus (or at least a lot of ’em) could hold for connections so these just misses no longer occurred.
• The challenging trade off – The challenge with this one is that holding one bus up in a system risks negatively impacting further passengers, routes and trips down the line since everything is connected together. 

  Don’t get me wrong: By “holding a bus” I’m not talking about all of the heroic kindnesses that take place everyday where drivers wait a few more seconds to enable a running passenger to board.  In this case I’m talking about requests to hold a bus at a point for three minutes or more in the hopes that a connection will show up.

  • Even when it’s a three minute hold–which many systems commonly allow at the Operator’s discretion for key connections–there can be cascading effects that happen.  Down the line other connections and arrival times may start missing each other and negatively affecting more people than were helped by the initial hold.
  • As the hold time increases, these downstream negative repercussions increase exponentially.  Indeed, hold too much and not only will you have many, many other missed connections but the bus will be arriving at its terminus point after it was supposed to leave on its next trip.
• The bottom line – Ideally, connections are best addressed through operating trips more frequently rather than holding buses.  Yes, this means that there will be cases where you just miss a connection.  And yes, there are cases where more time needs to be built into system schedules for crucial connections to be met.  But in terms of overall systems, transit dollars are usually much better spent on increasing frequency than investing in buses sitting still in the hopes of a connection.

Classic Three Minute Ask #3: “This road network change won’t really affect transit all that much, right?”

Yes, each of the above represents one vehicle on the road. But when allocating space and time, the one that is carrying a whole lot more people should be worth a LOT more.

Whereas the other requests are typically made directly to a transit agency by passengers or staff,  this one often arises through citizen requests to a municipality’s engineering or public works department to change road network composition or speed.  Considerations about transit impacts may come as an afterthought or may be downplayed.

• Why road network changes DO make so much sense – We all want safer, more vibrant streets that make it easier to get around on foot and by bike.  These modes are the most vulnerable–and also the ones that contribute to great transit use and sense of place–and they deserve quality space. It stands to reason that slowing down cars and more democratically distributing space to people (not vehicles) through how we allocate road right-of-way is a key way of achieving these benefits.
• The challenging trade off – I totally support the effort to build more complete streets.  AND, where I sometimes see issues is when the number of people in fact being carried on transit seems to be disregarded in a road network change.  Usually this is due to lumping buses into the same category as cars. A three minute delay to a car driver through road right-of-way reallocation sounds like a good incentive to encourage travel by other sustainable modes.  But if buses are lumped into that “what’s the big deal, delay is okay” strategy without mitigating treatments, these changes actually punish people who ARE using sustainable modes.  They also either make transit less frequent or more expensive.
  • Road network changes that produce delays for transit make trips slower for passengers. Three minutes sounds small but on a 30 minute long trip, that’s a 10% increase in travel time.
  • Beyond the direct personal impacts, there is also no such thing as “free” time in a transit system.  If you want your system to stay on time, that additional three minutes now needs to be added to the schedule for each affected trip and direction.  And if the road network changes make congestion more randomly volatile, even more time will be needed per trip.

As explained in the post on scheduling tradeoffs, that time has to come from somewhere: either more investment will be needed in the system (just to maintain the same number of now slower trips) or the number of trips will need to be cut (resulting in less frequency, more crowding and a greater potential for full buses passing up waiting passengers).

• The bottom line – I’m definitely not suggesting that we slow our efforts to make more complete streets.  What I am saying is that if we’re going to do it, do it right.  Recognize that buses are not cars or “general purpose” traffic and that small-sounding increases to transit travel time actually have a sizable impact when multiplied across many trips.
  • Slowing down local neighbourhood routes is less of an issue and may also make sense depending on the nature of the street and land use.  But for highest order frequent and regional routes, mitigating strategies (bus lanes, queue jump lanes, signal priority, etc.) should be considered in tandem with improvements to walking and cycling to ensure we truly build quality transportation choice in our communities.

Summing Up

Okay, so now you have seen into the dark window of my soul.  Like I said, my intent in writing this was to provide some insight into what goes through my head when I hear someone tell me that a change will only add three minutes.

However, I also want to underscore that you should keep asking.  I firmly believe that each of us are experts in our own transportation.  The expertise and perspective that you bring based on your particular trips, routes or neighbourhood is valuable and folks like me want to (and need to!) hear it because that’s how we evolve systems and make them better.

Just be aware that there will be trade offs to your suggestions.  And if you use the three minutes line, I’ll get a little twitchy.