Everyone who's been anywhere near downtown in the last year or two knows how much longer it takes to get from point A to B than it used to. San Francisco has, maybe fictitiously, never been a city one associates with chronic traffic the way we do Los Angeles, but the booming economy, along with a host of other factors, have made traffic within the city limits way worse than it's ever been, and you don't need a study to explain this. Even Dianne Feinstein is beside herself about it when she comes back to town. Nevertheless, the Chronicle commissioned a study, and the results are predictable.

The study by traffic information company Inrix found delays in both directions of traffic at several corridors and intersections in downtown ranging from 20 seconds to over a minute. These included Montgomery Street between Bush and Market, where traffic is clearly slower than it was in 2014 in the southbound evening commute out of town; Harrison Street and Embarcadero near the Bay Bridge on- and off-ramps during both the morning and evening commutes; and Market Street between Third and Seventh Streets in both morning and evening, in both directions.

Below, the bullet pointed factors causing this:

• Inbound traffic on the Bay Bridge is up 2.2 percent over a year ago, and inbound traffic on the Golden Gate is up 1 percent. We don't know, however, how many more cars are arriving in town from the South Bay.
• The middle of the day isn't showing any relief, while everyone rushes around at lunch. Mid-day traffic volumes downtown "are nearly as high between 11 a.m. and 1 p.m. as during the morning commute."
• Uber and Lyft have added as many as 15,000 new vehicles to city streets. While some of these replace traditional cabs that have gone out of circulation, it still probably accounts for well over 10,000 new cars racing around town at all hours of the day.
• And let's not forget all the SpoonRocket, Caviar, PostMates, and Munchery delivery people.
• Overall increases in volume and congestion mean that the impacts of individual double-parkers become that much worse. Between Uber drivers pulling over to pick up riders and delivery trucks, downtown has become that much worse of an obstacle course particularly on weekday mornings and afternoons.
• Construction is causing street closures and lane blockades in various parts of town. The MTA is on track to issue some 1,700 separate permits for blocking traffic in the first half of 2015 alone.
• The Central Subway construction and Transbay Terminal have been occurring for several years in the heart of SoMa and Union Square, partially blocking or disrupting routes along Fourth Street, Stockton, Mission, and First and Second Streets.
• Drivers are jerks, and creating more gridlock than ever. Per the Chron, "Officers have issued 82 percent more 'don’t block the box' tickets through spring compared with last year, and the number of double parking citations is up 53 percent."
• Also, there's the factor of "emotional use of the gas pedal." People in a hurry, or stuck in particularly sluggish traffic or derailed by a construction blockade, tend to get more aggressive and can only lead to the perception that the congestion itself is worse than it actually is.

But you knew all of this already, right? Cue the bicycle folks telling you to stop using cars for anything.