The PeMS Forum

October 21, 2010

Corridor Module- Congestion: Overview

Filed under: Uncategorized — Chad Riding @ 9:42 am

In the corridor module, accessible through Facilities & Devices -> Corridors, you can see congestion plots for every day in an entire month and every month in an entire year.  The graphic below shows the congestion plots for each day in September 2010 along SR-91 East in Orange County.  The horizontal axis represents time while the vertical axis represents direction of travel and distance.  The yellow and red colors represent areas of slow speeds.  From the graph you can see that this eastbound direction experiences most of its congestion in the afternoon, and a potential bottleneck is visible for most weekdays in the month.  Which weekday is a holiday?  Find the weekday with no congestion and you will have the answer.

Note: If you can’t see the image below clearly, click on it to see an enlarged version.

October 6, 2010

Data’s Available for Rural Districts, Too

Filed under: Uncategorized — Chad Riding @ 8:15 am

Hello, Fellow PeMS Users!

Did you know that data is available for those parts of California that do not have automated detection (called ITS stations or VDS in the PeMS)?  While automated detection is vital for calculating performance measures, the data available all over the state still provides important information about California’s state highway system. This information consists of traffic count (census) data, Lane Closure System data, and incident data (from the CHP and TASAS).  The traffic count locations are represented by the yellow markers on the PeMS Inventory Map and contain hourly and daily traffic counts, in some cases dating back to 1993!  Weigh-In-Motion (WIM) data is also available, providing counts by vehicle classification.  The Lane Closure System is found in the PeMS Real-Time Map and in its own section of the PeMS, under the Events tab.  It provides information about every scheduled lane closure in the state.  Incident locations also are shown in the PeMS Real-Time Map and incident details are found under the Events tab. 

So if you need data for districts 1, 2, and 9, the PeMS is still your place to go, so log in and jump to those districts to take a look!

Best Regards,

The PeMS Team

P.S.  The pictures below may appear a bit stretched or shrunk.  Please click on the picture to see it in a larger size.

September 28, 2010

Delay by Day of Week

Filed under: Uncategorized — Chad Riding @ 2:03 pm

Good Day, PeMS Users-

As part of our effort to spread the word about PeMS, we’re going to be making occasional blog posts to highlight some of the features of the PeMS.  Welcome to our first post!

Analyzing Delay by Day of Week

Which day of the week do you think has the most delay?  Thursday, perhaps?  Maybe Wednesday? Or even Tuesday?  Nope- all wrong.  The correct answer is Friday.  Yes, according to statewide data from the first half of 2010, Friday experiences the most delay, as measured at both the 35 mph and 60 mph thresholds (see graphs below).  Traditionally, people assume the most congested day is Thursday because Friday is when people presumably come in late, leave early, or take the day off for a mini-vacation.  But the data refutes this assumption.  Why do you think Friday has the most delay?  Our hunch is that it has to do with the combination of regular work trips and a higher number of leisure trips.



To get this report from the PeMS start page, go to Performance -> Aggregates -> Day of the Week.  For the Quantity, put in Delay (V_t=60) and Delay (V_t=35).  The time range is from 1 January to 30 June 2010.  Maybe you can take a minute to run the same report for a particular district or freeway.  Do you find the same trend?

You may leave comments on this post or discuss it in the forum.

Best Regards,

The PeMS Team

July 1, 2010

Recent PeMS Upgrades

Filed under: Uncategorized — Chad Riding @ 8:28 am

Good Morning, PeMS Users-

These past few months have been busy ones for the PeMS, with the transition to the Ct PeMS now complete and a significant upgrade made. Here’s a list of the changes that have been made to the PeMS:

  • The transition to the Ct PeMS is now complete. It is fully within Caltrans’ firewalls and on Caltrans’ servers. The website at <<>> is now the official production version of the PeMS.
  • The new PeMS 10.3 is up and running. You’ll have noticed many changes to the site. These include enhanced usage of maps throughout the site, on every webpage. Users can click on these maps to access interactive, dynamic mapping to see real-time data and sensor inventory.
  • New equipment has been installed to provide optimal site performance. There are new servers and other equipment, and so PeMS users should find the site performs much faster than it used to.

More improvements are coming in the next few months. To make the most of these improvements, your feedback is always welcome. You can leave this feedback under the Forum topic “Suggestions.”

Also Jane Berner, Senior Transportation Planner, in the Headquarters Division of Traffic Operations  is in charge of PeMS research and development. If you have any questions or suggestions regarding the future direction of the PeMS, please contact her at

Best Regards,

The PeMS Team

January 5, 2010

FAQ on the Transition to CT PeMS

Filed under: Uncategorized — Chad Riding @ 2:20 pm

Good Day, PeMS Users!

To help use Ct PeMS, we have a Frequently Asked Question page specifically about the transition to CT PeMS. It is found under the link labeled “Transition to Ct PeMS FAQ.” If you have any suggestions on how to improve this page, please let us know by contacting Jane Berner at or (916) 654-2843.


The PeMS Team

December 30, 2009

More on the Migration to Caltrans PeMS

Filed under: Uncategorized — Chad Riding @ 10:59 am

Good Day, PeMS Users-

We have some important information to share with you regarding the PeMS.

As of December 31, 2009, all PeMS users, including those from Caltrans, other public sector agencies, the private sector, and value-added resellers (VARs), will be directed to the Ct PeMS website at <<>> The good news is that you can use your same user name and password from the UC Berkeley PeMS site on the Ct PeMS website.

We realize that users may experience decreased system performance while using the new site. We are currently working to purchase and install new servers to fix this performance problem, which should take approximately 3 months. If you have any questions, including those regarding VAR accounts, please feel free to contact Chad Riding at or at (916) 653-4310.


The PeMS Team

December 2, 2009

Difficulties with the New Ct PeMS

Filed under: Uncategorized — Chad Riding @ 2:09 pm

Good Day!

We know that many of you may be experiencing extreme difficulties with the Ct PeMS website.  Due to Office of the Chief Information Officer (OCIO) policies, we currently cannot purchase new servers for the system.  As soon as OCIO allows us to, we will purchase new servers and greatly improve the functionality of the PeMS.

If you have any questions or comments about this, please contact Jane Berner at

-The PeMS Team

November 24, 2009

Caltrans (Ct) PeMS

Filed under: Uncategorized — Chad Riding @ 9:20 am

Good Day, PeMS Users!

We are transitioning the PeMS production version to the Caltrans (Ct) PeMS website found at  You will be automatically redirected to this site.  You will be able to use your current PeMS login on this website, and the user interface with its functions will be the same as the UC Berkeley PeMS site.  During this process you may find that the CT PeMS website runs somewhat slower than the previous UC Berkeley site.  We hope to have this problem corrected as soon as the IT equipment is brought up to speed.  Please refer any questions to the forum under ‘Ct PeMS Migration,’ or to Jane Berner at


The PeMS Team

August 25, 2009

Welcome to the PeMS Forum!

Filed under: Uncategorized — Chad Riding @ 9:16 am

We are pleased to unveil the new PeMS Forum.  This is a place where you can ask and answer questions about the PeMS.    The purpose of this forum, then, is to allow the users of the PeMS to learn from each other how to get and interpret data about transportation in California.  The forum is found at the link at right labelled “Forum,” and instructions for signing up are found at the link labelled “How to Register.”  You will also find a glossary explaining terms and concepts about the PeMS, as well as a Frequently Asked Questions page explaining this forum.

If you have any questions or comments about this forum, please contact the Website administrator, Jane Berner at

Best Regards,

The PeMS Team

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