PRISM ENGINEERING, SAFETY FIRST FOR TRAFFIC ENGINEERING & PLANNING
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traffic engineering

multi-modal traffic engineering
integrating the bus, the bike, the ped, the car, the train

​photo/video © 2019 PRISM Engineering
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SAFETY.   Above all else, Safety is the first priority with Grant Johnson, Traffic Engineer. Regularly examines safety of transportation systems and traffic control devices...with INTERNATIONAL EXPERIENCE including China, to determine if the installations are safe, normal, and customary.  Was common sense used?  Was the traffic control installation  standard according to AASHTO, MUTCD, or State and Local Standard Plans?

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Grant P. Johnson, TE is a registered Traffic Engineer in the State of California, the only state in the union with this special distinction.  Now a requirement of many government jurisdictions to qualify traffic studies, the Traffic Engineer is being asked to sign documents as an authority on the subject of all things pertaining to traffic and regulation.  In Expert Witness testimony and research, the title of Traffic Engineer enhances credibility.   ​
    
​He is currently working on several traffic engineering and planning studies, as well as numerous cases as an Expert Witness throughout Northern, Central, and Southern California cities and counties, including working with Caltrans.
CONTACT info
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Expert Witness for
​Industrial and Commercial Lighting IES standards
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Grant Johnson has current "hands-on" experience in all things traffic engineering and transportation planning.  When making a visit to a project site or an accident site, he gathers the best information and evidence possible to develop a report, signed by a Traffic Engineer registered in the State of CA.

As a commercial pilot for drone cameras licensed by the FAA, he is fully registered and highly skilled with a flying camera that he uses for commercial purposes. As an information gathering tool, he has found that properly placed drone footage can significantly enhance understanding of the situation with unique visual perspective.

Taking video of streets, intersections, parking lots, parking maneuvers, etc., using multiple drones simultaneously if needed, he can get all needed angles and make a better assessment of the technical situation, from a bird's eye view, as well as the drivers perspective in the car. 

The elevated video(s) can show signal operations from multiple approaches simultaneously and capture signal malfunctions or even mis-programming.

From a defense standpoint, he can determine the proper design of intersections, signal systems, parking, or freeway ramps, etc.  Using the Manual of Uniform Traffic Control Devices, or the MUTCD as a starting point, he can defend a properly installed traffic control on a street system.

He has the experience needed to detect and determine proper/improper design or installation of traffic control devices by observing from a high level view, combined with drivers eye ground level video, to see how drivers see the situation(s) and react to a poorly designed or outdated installation.
  • Do drivers consistently run red lights at or near the accident location?
  • Do they disregard traffic control of another type, such as a stop sign?
  • Is the design poorly thought out or implemented?

In Marin County, Mr. Johnson worked with County Counsel and the Department of Public Works to study and determine the problems at the Four Corners intersection, where a lawsuit was brought against the county after an accident. PRISM Engineering worked with the county staff to provide a new design for the intersection that addressed existing problems and created a more modern and safe standard, for not more than the cost of paint and some minor engineering design fees.

PRISM's custom design actually helped to slow speeds through installation of special striping and pavement markings, using the available pavement space to relocate striping, adjust the stop bars to better locations, and better define the travel pathways (less ambiguous) to achieve smoother flows of vehicles and bikes. PRISM creates movies from our videos to clearly show the complete picture from many viewpoints.

Using this capability to quickly make the movie, we can showcase how drivers behave in the accident location, good or bad behavior, which helps to establish the patterns with visual proof.   All accident records in the vicinity are researched to see if there are significant data or not, to show a pattern of similar accidents.  

Mr. Johnson is an expert in regulation and design standards such as the MUTCD and related materials and manuals on lighting, road and intersection design. He can determine if a roadway has been properly or improperly designed, and also knows the traffic engineering law and principles of safety related to all traffic control devices in use today.  He also personally drives through the site and inspects traffic conditions and sight distance from the drivers point of view, to make a determination if there are factors related to safety compromises or safety enhancements for all drivers, pedestrians, and bicyclists.

His engineering work in China enhanced specific skills for great attention to detail.  In the physical transportation world, he has extensive experience in checking complex plans for construction of China's major High Speed Rail projects dealing with regulations and standards and safety conditions.


Given the top inspection responsibility there on site as the Chief Site Engineer (CSE), he was in responsible charge of all quality control and safety on a 70 kilometer section of high speed rail construction, a new HSR rail line connecting Beijing to Shenyang in Northern China.  The job included:
  1. Overseeing the entire construction process,
  2. Having "Stop Order" authority over construction companies there, to shut down construction if standards were not met or if safety was ignored
  3. Closely examining and reviewing construction and design plan sheets in the office, to be prepared in the field to inspect specific high speed rail projects in the entire 70km section, including tunnel, bridge, box culvert, open cut, piles and piers, and foundations construction.

As a part of the job, surprise inspections in the field were conducted to make sure plans were followed closely by construction companies, and to document all activities and exceptions for correction by photo and video on the numerous variety of construction sites. Regular formal meetings were held with the national HSR authorities in the Communist government, where he reported on compliance on the site and for all aspects of construction and safety protocols, as well as quality of materials.  He kept a daily journal, a spreadsheet database, and prepared weekly extensive reports written in English and in Chinese Mandarin officially documenting all of this information for the government.

​Grant says: "The work was challenging and trained my eye for looking for all details of transportation construction, and installations of what was done right and what was done incorrectly."

When I examine the transportation systems in the US where an accident took place, whether it be a bike, a pedestrian, a train, freeway, city street, or two-lane highway, I'm looking for the big picture of whether the traffic control or road design or construction was done properly with safety in mind, according to the accepted design standards such as the AASHTO Green Book, the MUTCD, or from Engineering Judgment by Inspection and Analysis and Experience.

Commercial Remote Pilot


​Multiple Drone Cameras


​Inspect Freeways, all Roads


​Legal Design Strategy


​Find out: How is it Working?


​Traffic Engineering DETAILS


​High Speed Rail Construction


​A Better Bigger Picture

I have 39 years of on-the-job experience with all things related to traffic and transportation engineering. I'm going to be able to find the details more quickly and put together a better, bigger picture.
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PROJECT HIGHLIGHT: Signal Design Modification and Signing and Striping Plans

In City of Vacaville, Solano County: 
STRADA 1200 apartments, a Guardian Capital project 
Intersection Modification.  Signal Design Modification. Signing/Striping Modification

New Signal Plans: Year 2019 (prepared by PRISM Engineering)

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New Signing and Striping Plans: Year 2019 (prepared by PRISM Engineering)

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Project Scope:
Intersection converted from 3-way T-intersection to a full access four approach intersection. New road constructed.
​PRISM conducted a complete inventory and inspection of Signal Equipment, signing, and striping / pavement markings. Surveyed pedestrian activity.
Photos and video logging.
New signal heads needed.
Complete replacement of video detection to latest tech. Revised striping. New Crosswalks needed. Signing revised.
​Signal interconnect maintained between local intersections. 
​---New signal plans needed for bid. 
---New signing and striping plans needed for bid.
---Equipment Schedule completely revised.
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New Signal / Striping Plans: Year 2019

       source: PRISM Engineering

25 year old "As-Built"
(original signal design)

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       source: Vacaville Public Works
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-ON-CALL SERVICES-

In Marin County:  Four Corners Intersection, Improvement Alternatives (2017-2019)
                                 Panoramic Highway at Muir Woods Road

Observations. Video. Sight Distance. Synchro. Intersection Design.
Traffic Calming. Reduce Accidents. Increase Safety.

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FOUR CORNERS work_order_report.pdf
File Size: 38729 kb
File Type: pdf
Download File

SAFETY FIRST

​Google Street View UPDATES to Four Corners Intersection Final Alternative (Photos Mar 2021).   
Designed Jan 2019, Constructed 2021 based on PRISM Engineering Design

​EMERGENCY RESPONSE!  Fire Engine Response Study.    Feb 2019, Fairfield, CA

PRISM Engineering conducted a comprehensive emergency fire engine response time study to determine if adequate emergency response times are in place according to established standards (NFPA 1710). Out of nine nearby fire stations, 3 were within the standards, and only one needed to be. A complete report with tables and graphics was prepared to document all findings, and detailed times on all travel paths. Google Maps App was also researched to make comparisons of actual drive times in the field, and to verify.    The purpose of the study was to find out through engineering methods (research, measurements, analysis, and summary) what fire engine response times from various fire stations proximate to the project site would be, by physically measuring and video recording actual driving times from each station to the site, adjusting times for red lights along the way, considering the effects of traffic congestion, and taking into consideration what happens when a fire engine deploys traffic signal pre-emption to bypass a red light at an intersection, etc. In addition, “big data” from Google Maps was also used, a publicly available data set that documents the ranges of time that drivers experienced along a certain path while using the Google Maps App.  A detailed info-graphic and summary matrix and report were prepared to show optimum pathways and times from nine different nearby fire stations to the project site, during the “worst case” pm peak hour time period.

MARIN COUNTY ON-CALL SERVICES. Jan 2019
​Four Corners Intersection: Final Alternative.
Traffic Engineering.

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Engineering design and drawing by Grant Johnson, TE Registered Traffic Engineer © 2019
Work completed for Marin County Department of Public Works.
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COMMENTARY ON IMPROVEMENTS BY GRANT JOHNSON, TE :

  • This intersection will undergo a huge safety and design improvement. Traffic will slow significantly to about 20 mph.  Traffic operations will improve with a focused intersection. Bikes can safely navigate, etc.
  • The deflection angle for the NB approach matches deflection angle used in single lane approach or dual lane approach modern roundabouts and as published in the MUTCD. This angle has a traffic calming influence. It will slow traffic to safe speeds, such as 20 mph. The radius of the approach entry curve is 100 feet.  This also applies for the southbound movement, but the curve is on the exit.
  • Striped islands are being used, with thick wide lines to clearly delineate the area that should not be used.  
  • The centerline of the SB approach has been modified to expand to a short loop area about 3 feet wide and then tapering back to the center, providing some better definition for the vehicle pathways.  All vehicle pathways have been checked, are tangential to the lane curves, centerline striping and edgeline striping at intersection approaches clearly directs vehicles in a smooth and logical path.  It has been designed for smooth movement of vehicles, through 12 foot wide lanes.
  • The turns in the intersection according to the proposed striping shown, have been tested with the Caltrans HDM truck turning templates for a large bus and pass the test.
  • The Muir Woods EB approach has been significantly moved forward, as well as the WB approach.  Stop signs have been relocated. It is possible to see previous markings through the slightly translucent black overlay layer.
  • The Panoramic Highway NB approach has also been moved forward significantly, and the length of the left turn pocket has increased from and existing 115’ to 140’ with the proposed striping.  The intersection as a whole is much tighter together.
  • The warning signs proposed will guide drivers that a 20 mph advisory curve is at hand.  
  • The centerline striping for the NB and SB approaches has been extended through the intersection according to the MUTCD standards on Fig. 3A-112(CA).  This also serves as a kind of refuge for the left turns out from NB Panoramic Highway.  
  • The NB approach and the SB approach have both been modified with Speed Reduction Markings for the through lanes. MUTCD Fig. 3B-28 details the size and spacing of the markings, and this plan has been implemented accordingly.  These markings should be sufficient to alert drivers that a slowing in speed is expected, and with the warning sign clearly in place at the end of the markings, drivers should have slowed to 20 mph, according to the curve and deflection implemented. It is possible to also install rumble strip traffic calming devices, but not necessary if these other devices are installed.

AERIAL VIEWS and
​NEW INTERSECTION DESIGN

SIGHT DISTANCE and SPEED STUDIES

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International 国际 Highlight

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Traffic Engineering
TRAFFIC OPERATIONS:  MICROSIMULATION TRAFFIC MODELING 

Since 1995 when it was first released, PRISM Engineering has been using Synchro and SimTraffic to analyze traffic and design signal systems.  
PRISM has also used many of the other microsimulation software packages in existence today, but prefers the SimTraffic software because it is 1) Ubiquitous, 2) Not easily manipulated to get significantly different results from default setup, 3) Works with Synchro and all the specific lane geometry and traffic operations data already in that software, and is readily shared with clients.
​In this infographic example, Grant Johnson, TE emphasizes multiple levels of information in a simple graphic, showing street aerials with volume-based HCM level of service composited, actual freeway traffic flows, color coded travel paths (red=stop and go LOS F, green=free flow LOS D or better), and microsimulation level of service shown on long paths of stop and go flows.
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PRISM Engineering creates detailed and accurate microsimulation and analysis models.  We collect "Big Picture" data to see the big picture.

Synchro / SimTraffic

​Using industry standard microsimulation software like Synchro and SimTraffic, Vissim, and Paramics, our analysis approach is to have high levels of detail to facilitate better answers that mirror how the public already perceives their traffic experience.
​ PRISM knows that reporting "LOS C" when the public is experiencing LOS E or F is a big mistake, and that analysis tools must reflect reality.  That is why we collect data with aerial and street level VIDEO and also take Saturation Flow Rate samples to better understand local driver behavior and adjust software accordingly.
​photo/video © 2019 PRISM Engineering
PRISM Engineering routinely hires outside services to collect big picture data, and regularly collects / films aerial video in 4K resolution in order to study and analyze real world traffic conditions as a system of intersections and driveways, and not as isolated intersections.  This data used in our consulting practice enables an understanding of the bigger picture which can not be obtained from analyzing traffic count data alone.

Traffic Engineering
DETAILED INTERSECTION ANALYSIS and DESIGN, based on TRAFFIC PROJECTIONS

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-ON-CALL SERVICES-

In the City of Vacaville:  The Farm at Alamo Creek TIA (2017)
                                            750 unit planned Specific Plan Development

CUBE model. Synchro. HCS Freeway. SimTraffic. Intersection Design.

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The Farm at Alamo Creek TIA.pdf
File Size: 54898 kb
File Type: pdf
Download File

Report Samples. Trip Generation. CUBE 6.4 Traffic Demand Model. Excel Database. Synchro HCM Analysis. Mitigations

Traffic Engineering
MICROSIMULATION MODELS to SIMULATE REAL TRAFFIC FLOWS after calibration

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​Synchro
and
SimTraffic
PRISM Engineering has worked with numerous cities and county and regional agencies in preparing a variety of traffic studies nearly all using the Synchro / SimTraffic software package because we can share files with reviewing government agencies during the review stages of the study.  We have completed over 100 traffic studies in Nevada County, Placer, El Dorado, Amador, Calaveras, Tuolumne, Madera, Fresno, Merced, San Joaquin, Solano, Sacramento, Yolo, and Contra Costa Counties.  In addition, we have completed numerous studies in various cities such as Vacaville, Dixon, Davis, Lodi, Stockton, Grass Valley, El Dorado Hills CSD, Jackson, Angels Camp, San Andreas, Los Banos, Fresno, Clovis, Folsom, Placerville, Nevada City, Auburn, Truckee, South Lake Tahoe, etc.
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A SimTraffic network created by Grant Johnson, TE in Marin County at US 101 and SR 131 interchange is overlaid onto an aerial photograph in SynchroPro / SimTraffic microsimulation software.  Four signalized intersections are coordinated with signal cycle offsets.  These models are used to examine changes in signal timings to get better operations results. They can also be used to examine new roadway and driveway connections, expansions to intersections and changes of lane geometry, etc.  In this study it was determined that signal timing changes could reduce delays and change an LOS F condition for a frontage road side street to LOS D conditions without significantly impacting other movements.

Traffic Engineering
TRAFFIC IMPACT STUDIES and ANALYSIS​

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PRISM Engineering staff has conducted numerous traffic impact studies, large and small, over the past two decades.  
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TRAFFIC IMPACT STUDY: City of Vallejo, CA Charter School Alternatives Analysis.  Examined: 
  • Traffic Demand Management
  • Intersection Mitigation
  • Phasing of School Growth
  • Future Level of Service Analysis
  • Microsimulation Check Technology
traffic_study_final_vallejo_charter_school_4.pdf
File Size: 4844 kb
File Type: pdf
Download File


CORRIDOR STUDY:

City of Folsom, CA
​Riley Blvd Corridor Study
  • Alternative Median Treatments. 
  • Calming of Traffic
  • Enhancing Safety
CAD based drawings and renditions created by PRISM Engineering

Traffic Engineering
SIGNAL DESIGN

BUILT: El Dorado Hills Green Valley Road Corridor Signal and Interconnect Design by PRISM Engineering

In this On-Call Services work order, PRISM Engineering worked directly with El Dorado County Department of Transportation Design Staff to create the signal design layers in the extensive AutoCAD design file with XREF overlays. Grant Johnson, TE was project manager of this work effort and designed the conduit runs, pole and detector locations, signal phasing and diagrams, signing and striping.
PRISM Engineering has completed numerous signal design projects over the years, and integrated these plans with development applications where street and intersection improvements are required as a part of a traffic impact analysis.  PRISM has the ability to take things from the planning stage of forecasting traffic, to the analysis stage of determining intersection and road segment improvements, and warranting of traffic signals for a new installation, or the modification of an existing signal expanded to include more lanes, etc.  We have also designed inter-connected signal installations where traffic volumes between intersections are coordinated with offset signal cycle timings, and analyzed using SynchroPro and SimTraffic microsimulation.

International Highlight Project in 重庆市 ChongQing, China

Signal Timing and Capacity Throughput Research Study in ChongQing China's Jie Fang Bei's Winding Mountain Road Intersections.  6 Camera Angles of each Phase and Movement.
videography and edit: G. Johnson

Traffic Engineering

PUBLIC PRESENTATIONS, sample

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http://www.marincounty.org/depts/bs/meeting-archive
In this case he spoke before the Marin County Board of Supervisors on a hotly contested and controversial topic and discussed the traffic operations study results, and how information was shared with Caltrans, etc.
Link to local newspaper story on this BOS decision and process:
 story: http://www.marinij.com/article/NO/20160413/NEWS/160419920
Grant Johnson, TE has extensive experience in making public presentations on technical topics, and in making them understandable and credible.  
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6. Data Collection using HD video and Digital Counters

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Website Copy and Media © 2016-2023 b y Grant Johnson, PRISM Engineering
  • Home
  • SERVICES
    • SERVICES
    • EXPERT WITNESS TRAFFIC ENGINEER
    • EXPERIENCE
    • Complete Streets EVOLVED >
      • Complete Streets
    • TRAFFIC ENGINEERING
    • PROJECTS >
      • SAFETY FIRST focus at PRISM Engineering
    • TRANSPORTATION PLANNING
    • HSR Construction Inspection Experience
  • Contact
    • About
  • TRAFFIC FACTS
    • NEWS
    • INTERNATIONAL TRAFFIC FACTS
    • CALIFORNIA HIGH SPEED RAIL TRAIN TO NOWHERE?
    • SAFETY FIRST Examples
    • PED DANGERS: Death by Subway and Death by UBER
    • Modern Roundabout Examples by PRISM Engineering
    • AUTONOMOUS VEHICLES in Traffic >
      • AUTONOMOUS CAR DISRUPTION
      • Autonomous UBER Fatal Accident
    • How About That BIKE COMMUTE?
  • CHINA TRAFFIC 2018
    • CHINA TRAFFIC 2018
    • HSR High Speed Rail
    • CHINA BLOG
  • STUDIES
    • Watsonville CEIBA School Traffic and Safety Investigation
    • Pasadena 253 S Los Robles v2