Term Project: Signal Warrant Analysis     Biscayne Boulevard and NE 18th Street                                           Incorporated Miami-Dade County, Florida

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Term Project: Signal Warrant Analysis

 

 

Biscayne Boulevard and NE 18th Street

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Incorporated Miami-Dade County, Florida.

District VI

Midtown Miami Arts District

1. Executive summary

The goal of this report is the presentation of the results of a signal warrant analysis conducted for the intersection of Biscayne Boulevard (U.S 1) and NE 18th Street. The motivation behind this study, is the complaints, and the requests for a traffic signal at the intersection, by citizens living in the area. All the results, conclusions, and recommendations presented in this report are meant to improve safety at the location, and have been generated from the existing conditions, crash analysis, and signal warrant analysis for the location.

 

Biscayne Boulevard and NE 18th Street are both four lane highways, and the study location, the intersection of the two highways, is a four-leg, stop controlled intersection. Chapter 3 of the FDOT Manual on Uniform Traffic Studies (MUTS), and chapter 4 of the 2009 Manual on Uniform Traffic Control Devices (MUTCD), were used to determine if the signal at Biscayne Boulevard and NE 18th street was warranted. To determine whether the traffic control signal was needed, the existing conditions, the safety of the study location, and the possibility of improvement were analysed. More importantly, the applicability of the following traffic signal warrants were evaluated:

 

· Warrant 1, Eight-Hour Vehicular Volume

· Warrant 2, Four-Hour Vehicular Volume

· Warrant 3, Peak Hour

· Warrant 4, Pedestrian Volume

· Warrant 5, School Crossing

· Warrant 6, Coordinated Signal System

· Warrant 7, Crash Experience

· Warrant 8, Roadway Network

· Warrant 9, Intersection Near a Grade Crossing

 

The signal warrants found to be applicable and included in the study are:

· Warrant 1: Eight hour vehicular volume

· Warrant 2: Four hour vehicular volume

· Warrant 4: Pedestrian volume

· Warrant 7: Crash experience

· Warrant 8: Roadway Network

 

It was found, after analysis, that Warrant 1 condition A was satisfied for the 100% volume criteria, Warrant 2 was satisfied for the 100% volume criteria, Warrant 7 was found to be satisfied due to the a number of crashes preventable by a signal greater then Five, over a period of 12 months. Warrant 4 was not satisfied for both the 100%, and the 70% volume criterias. Warrant 8 Could not be satisfied due to a lack of data regarding traffic volumes during weekends. The satisfaction of the aforementioned Warrants, indicates that a traffic signal should be installed at the intersection.

 

2. Introduction

This study was initiated as a result of the request for a traffic signal at the intersection of Biscayne Boulevard and NE 18th St by citizens.The location is a 4-leg intersection that is a two way stop controlled on the east and west approaches. A signal warrant analysis, which is an overall study of the traffic conditions, pedestrian characteristics, and the physical characteristics of the location was performed in order to determine if the installation of a traffic control signal at the intersection was truly needed to improve traffic safety and efficiency at the location. Additionally, an evaluation of the existing conditions at the location, the development of an existing condition diagram, and a collision diagram, were also carried out, in order to better assess how the conditions at the study location could be further improved. Through this study, it was to be determined if the conditions needed to justify the installation of the traffic signal were satisfied, and if not, what other changes and implementations could be made in order to improve existing conditions.

 

Site Vicinity Map

 

3. Existing Conditions

The existing conditions analysis provided geometric characteristics and site conditions of the Biscayne Boulevard (U.S 1) and NE 18th Street intersection. Presented below you will find Table 1 where the reviewed analysis of the existing conditions and observed vehicle activity have been documented.

 

Table 1 Summary of Characteristics of Existing Conditions

Characteristic	Biscayne Boulevard (U.S. 1)	NE 18th St
Intersection Milepost:	N/A	Milepost 12.247
Area Type:	Urban	Urban
Segment Cross-Section:	4-5 Lane, 2 Way Undivided Paved 4 Legs	4-Lane, 2 Way Divided Paved 4 Legs
Posted Speed Limit:	30 miles per hour (mph)	30 miles per hour (mph)
Average Annual Daily Traffic:	37,100	5,200
Functional Classification:	Urban Collector	Urban Local Street
Pedestrian/Bicycle Facilities:	Sidewalk	Sidewalk
Transit Service/Parking Facilities:	Public Transportation	On-Street Parking
Lighting:	Cobra head luminaires and Post Top - both east and west bound	Post Top Lighting

 

3.1. Intersection Geometry

Biscayne Boulevard (U.S. 1) and NE 18th St is a two-way intersection, where NE 18th St is stop sign controlled while Biscayne Boulevard, at the intersection, is not. Biscayne Boulevard (U.S. 1) is a north-south, 4-5 lane urban collector that’s undivided. The north and south bound exclusive left-turn lanes are 205 ft and 215 ft long, respectively. The intersecting road is NE 18th St which is an east-west, divided urban local street with on-street parking on eastbound and westbound. The eastbound has two lanes, the right lane is used for turning right or going straight and it’s managed by a stop signal. The left lane is exclusively to turn left. The same design is used for the westbound potion of NE 18th St.

 

There are pedestrian facilities, public transportation on the major road going north, and no bicycle lanes in the vicinity of Biscayne Boulevard (U.S. 1) and NE 18th St. The posted speed limit along both roads is 30 mph.

 

3.2. Vehicle Activities

From reviews of the site, it was observed that there is congestion on the right lane of Biscayne Boulevard to the right lane of NE 18th St going southwest. The on-street parking that begins at the shoulder of NE 18th St going west causes this pause in traffic on Biscayne Boulevard going south. Additionally, the public transit stop going northbound on Biscayne Boulevard causes a build up of traffic on the northwest shoulder of Biscayne Boulevard (U.S. 1) and NE 18th St.

 

3.3. Traffic Data Collection

A 72-hour traffic count survey was conducted from Tuesday, January 29th, 2019 to Thursday, January 31st, 2019. The counts were taken on the major road of Biscayne Boulevard (U.S. 1) from both southbound and northbound and on the minor road of NE 18th St from both eastbound and westbound. The dates were selected to get data for the middle of week. The data collected from Appendix B shows that the daily combined volume of traffic from both directions of Biscayne Boulevard was 2,424 vehicles for the date of January 29th, 2019. For January 30th, 2019 the combined daily vehicle count was 2,449 vehicles and for January 30th, 2019 the combined daily vehicle count was 2,496. This averages to a 2,456 vehicle count at the peak hour of 4:15 PM which is when the daily volume of traffic is annotated. Below is Table 2 which illustrates the approach volume by intersection direction.

 

Table 2 Summary of Total Volume Entering the Intersection

Movement	A.M (9:00 - 9:45)	P.M. (5:00 - 5:45)
Northbound	736	1,295
Southbound	1,367	993
Eastbound	87	144
Westbound	229	259
Intersection Volume	2,419	2,691

 

3.4. Warning Signals

There is one warning sign for this intersection. It is located southbound on the major road of Biscayne Boulevard at the very beginning of the intersection. The sign reads, “DO NOT BLOCK THE INTERSECTION.” It is individually mounted roughly 20 feet from the curb radius on the southwest shoulder.

4. Crash Analysis

Five years of crash data (2012 to 2016) was obtained from FDOT Crash Analysis Reporting system (CAR) and reviewed. The analysis included an evaluation of crash trends and production of a collision diagram.

4.1. Historical Crash Trends

The crash data for the Biscayne Boulevard (U.S. 1) and NE 18th St study location is summarized in the expected values analysis table. The crash history was reviewed to determine if patterns or trends can be identified that indicate opportunities to reduce crash frequency or severity. The primary trends observed during the five year study period (2012-2016) are:

· 77 total reported crashes

· Angle crashes (25 or 32.5%) and Rear end crashes (24 or 31.2%) were the most frequent crash type within the study limits.

· 13 injury crashes were reported, 16.9% of total crashes. 6 of these crashes were angle crashes, 7.8% of total crashes.

· 0 fatal crashes occurred at the study location over the five year crash history.

· 16 crashes occurred in dusk, dawn, or dark conditions, 20.8% of total crashes. 6 of these were angle crashes, 7.8% of total crashes.

· 5 crashes occurred under wet pavement conditions, 6.5% of the total crashes. 1 of these was an angle crash, 1.3% of total crashes.

The histograms illustrate the crash trends for the study location. Appendix A contains crash summaries by year and an Expected Value Analysis (EVA) of the subject location. Figure 3 provides a collision diagram showing the location and type of crashes for all crashes over the five-year study period.

 

 

5. Signal Warrant Analysis

Here we will discuss the warrant analysis conducted at the intersection. The results of the study, and our recommendations for the improvement of the safety and efficiency of traffic flow at the location will be provided.

 

5.1. Intersection at Biscayne Boulevard and NE 18th Street

To conduct this study, and determine whether the conditions at the intersection of Biscayne Boulevard and NE 18th St warranted the installation of a traffic signal, we made use of the guidelines found within the chapter 3 of the FDOT Manual on Uniform Traffic Studies, and chapter 4C of the Manual on Uniform Traffic Control Devices (MUTCD). To justify the installation of a traffic signal at a specified location, both manuel require the satisfaction of at least 1 or more of the following warrants:

 

· Warrant 1, Eight-Hour Vehicular Volume

· Warrant 2, Four-Hour Vehicular Volume

· Warrant 3, Peak Hour

· Warrant 4, Pedestrian Volume

· Warrant 5, School Crossing

· Warrant 6, Coordinated Signal System

· Warrant 7, Crash Experience

· Warrant 8, Roadway Network

· Warrant 9, Intersection Near a Grade Crossing

 

The warrants found not to be applicable after analysis were:

· Warrant 3, Peak Hour: Because there are no facilities close to the study location discharging large numbers of vehicles over a short time.

· Warrant 5, School Crossing: There are no elementary schools and high schools near the study location.

· Warrant 6, Coordinated Signal System: Not applicable because the intersections to the north and to the south are 454ft , and 456 ft away, respectively.

· Warrant 9, Intersection Near a Grade Crossing: There are no grade crossings near the intersection.

The warrants found to be applicable and used to conduct the study were warrant 1(Eight-Hour Vehicular Volume), warrant 2 (Four-Hour Vehicular Volume), warrant 4 (Pedestrian Volume), Warrant 7 (Crash Experience). Due to the satisfaction of more than one of the aforementioned warrants, the study location was found to meet the criteria for the installation of a traffic signal.

 

5.2. Warrant 1: Eight hour vehicular volume

Warrant 1 required the satisfaction of one of the two following conditions:

· Condition A (The minimum vehicular volume) : Intended for application at locations where a large volume of intersecting traffic is the principal reason to consider installing a traffic control signal.

· Condition B (The Interruption of Continuous Traffic) : Intended for application at locations where Condition A is not satisfied and where the traffic volume on a major street is so heavy that traffic on a minor intersecting street suffers excessive delay or conflict in entering or crossing the major street.

For the study location, condition A of warrant 1, which required a minimum of 600 vehicles per hour on the major street, and 200 vehicles per hour on the minor street, for any eight hours, was found to be satisfied at the 100% volume criteria (see appendix B).

5.3. Warrant 2: Four-Hour Vehicular Volume

Warrant 2 is intended to be applied where the volume of intersecting traffic is the principal reason to consider installing a traffic control signal, and requires a certain volume of traffic on the major and minor street over any four hours of an average day.

 

For the intersection at Biscayne Boulevard and NE 18th Street warrant 2 was satisfied at the 100% volume criteria (see appendix B), which required a volume of more than 105 vehicles per hour on a minor street approach with two lanes, and a volume of more than 80 vehicles per hour on a minor street with one lane.

5.4. Warrant 4: Pedestrian Volume

Warrant 4 is intended for applications at locations where the traffic volume on a major street is so heavy that pedestrians experience excessive delay in crossing the major street, and requires a certain volume of traffic on the major street and a certain volume of pedestrian crossing the major street over any four hours of an average day.

 

For the intersection being studied warrant 4 was not satisfied for the 100% volume criteria, which required a volume of more than 107 pedestrians per hour crossing the major street, an that for each of any 4 hours of an average day, the plotted points representing the vehicles per hour on the major street (total of both approaches) and the corresponding pedestrians per hour crossing the major street (total of all crossings) all fall above the curve in Figure 4C-5 (see appendix B). The warrant was also not satisfied for the pedestrian peak hour, which required a pedestrian volume higher than 133 pedestrians per hour (see appendix B).

 

5.5. Warrant 7: Crash Experience

The Standard need for a traffic control signal will be considered if the findings of the engineering study conducted at the intersection meet all of the following requirements:

A. Adequate tests of alternative solutions that have been thoroughly conducted and observed. If these tests fail to reduce the crash frequency; and

B. Five or more crashes, of types that can be corrected with a traffic control signal, have occurred in a 12-month period, each individual crash involving property damage or personal injury apparently exceed the applicable determinations of a reportable crash; and

C. For each of any 8 hours of an average day, the vehicles per hour (vph) given in both of the 80 percent columns of Condition A in Table 4C-1 (see Section 4C.02), or the vph in both of the 80 percent columns of Condition B in Table 4C-1 exists on the major-street and the higher-volume minor-street approach, respectively, to the intersection, or the volume of pedestrian traffic is not less than 80 percent of the requirements specified in the Pedestrian Volume warrant. These major-street and minor-street volumes shall be for the same 8 hours. On the minor street, the higher volume shall not be required to be on the same approach during each of the 8 hours.

 

To satisfy condition A, a modification of the East/West LT Phase to ‘PROT ONLY’ Phase was proposed as an alternative. From the data recorded, the alternative did not reduce the number of crashes per year as expected. The alternative was tested from 2012 - 2014 and the reduction in crashes is not evident from the data. For example, for the top ranked crash type, rear end crashes, for 2012 the total was 2 crashes, 2013 was 7 crashes, 2014 was 8 crashes, 2015 was 3 crashes, and 2016 was 4 crashes. This shows that the yearly totals actually gradually increased over the course of the time period from 2012 - 2014 when the alternative was being tested and then decreased for 2015 and 2016.

 

Condition B speaks of five or more crashes, of crash types correlated with a traffic control signal, that have occurred in a 12-month period. From analyzing the data, we determined that the Rear End crash type and the Angle crash type both satisfy condition B. Rear End crashes occurred more than five times in two separate 12-month periods. As well, five or more crashes occurred in two separate 12-month periods for the Angled crash types. This is sufficient evidence for condition B to be satisfied.

 

Condition C is satisfied because for any 8 hours of an average day, the vehicles per hour (vph) are greater than 80% of Condition A and B in Table 4C-1. The 80% of both Conditions A and B are 420 vehicles per hour.

 

Due to the satisfaction of all the above conditions Warrant 7 has been found to be satisfied. (See appendix B)

 

5.6. Warrant 8: Roadway Network

 

The need for a traffic control signal will be considered if an engineering study proves that the intersection being studied provides sufficient proof that the common intersection meets one or both of the following criteria:

A1. The intersection has a total existing, or immediately projected, entering volume of at least 1,000 vehicles per hour during the peak hour of a typical weekday and has 5-year projected traffic volumes, based on an engineering study, that meet one or more of Warrants 1, 2, and 3 during an average weekday; or

B1. The intersection has a total existing or immediately projected entering volume of at least 1,000 vehicles per hour for each of any 5 hours of a non-normal business day (Saturday or Sunday).

A major route as used in this signal warrant shall have at least one of the following characteristics:

A2. It is part of the street or highway system that serves as the principal roadway network for through traffic flow.

B2. It includes rural or suburban highways outside, entering, or traversing a city.

C2. It appears as a major route on an official plan, such as a major street plan in an urban area traffic and transportation study.

 

For warrant 8 in this study, condition A1 is satisfied. For the start date of 01/29/2019 and Station 1801, the vehicle count from 7 AM until 4 PM coming from the North direction, the mean vehicles per hour is 2,065. This shows that during a weekday the condition is satisfied. As well, warrant 1 is satisfied meaning condition A1 for warrant 8 is justified. As stated in the requirements, there needs to be one criteria met and condition A1 is satisfied.

 

 

 

 

 

6. Recommendations:

The performed site visits allowed us to determine the signalization requirements of the intersection, and specific methods that should be applied for the safety of the drivers and pedestrians who make use of this intersection regularly.

It is suggested that the installation of some traffic lights, as well as improvement jobs on the road, can improve the traffic flow at the intersection, and decrease the accident rate of the previously analyzed crash reports.

 

6.1 Based on signal and warrant analysis:

 

Given the three warrants that the intersection meets, the installation of the following traffic control devices would be suggested:

1. Installation of a traffic control signal is strongly recommended, followed by a removal of the stop signs on NE 18 St, in order to improve traffic flow on NE 18th Street, and reduce angle, and left-turn crash rates.

2. Intersection warning signs on Biscayne Boulevard and NE 18th Street, on all approaches.

3. Installation of turning lane traffic for the car to integrate into the northbound biscayne and 19 St.

4. Push button pedestrian detectors on NE 18th Street, facing biscayne boulevard, in order to facilitate pedestrian crossing of the major street, and maintain their safety.

 

 

6.2 Based on Field Reviews:

 

The existing conditions and status of the intersection were evaluated through a site visit performed on 07/26/2020 . Based on the examinations this will be recommended:

1. Millin 1’’ of existing asphalt & resurfacing 1’’ of friction course.

6.3 Based on Crash Data:

The crash data analysis for the study location shows that out of the 77 documented crashes, from 2012 to 2016, there were a total of 25 angle crashes, representing 32.5% of all crashes at the intersection. Furthermore, 6 out of the 13 injury crashes reported were angle crashes. Additionally, 16 crashes, about 20.8% of total crashes occurred during darker conditions, 6 of which were angle crashes. It was also observed that the current lighting system of the intersection is out of date. Due to the high percentage of rear-end, angle, and night time crashes at the study location, the following actions are deemed necessary:

· Installation of a traffic control signal at the intersection, as an efficient measure for the reduction of angle crashes.

· Visible intersection warning signs for the reduction of rear-end crashes.

· Replacement of the luminaries with lighting installations of superior performance.

 

7. Cost Estimate and Benefit Cost Analysis

For the intersection in the study , a Benefit- Cost Analysis and a Net Present Value Analysis was conducted to find if the implementation of a signal at the intersection is an economically attractive solution . The improvements considered in these economic evaluations were :

 

1. Installation of traffic lights.

2. Push button pedestrian detectors

3. Replacement of luminares

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7. 1 Cost Estimate

The table below shows a summary of costs and total costs of the proposed improvements. The estimated total cost reaches a total of $ 619,686.00.

SAFETY IMPROVEMENTS COSTS
Roadway/Shoulder	$ 786.00
Signing and Pavement Markings	$ 17,584.00
Signalization	$ 212,900.00
CONSTRUCTION SUBTOTAL	$ 254,379.00
10% Mobilization	$ 27,275.00
20% MOT	$ 54,550.00
30% Contingency	$ 81,825.00
7% Administration	$ 30,548.00
15% Design(PE)	$ 65,459.00
20 % CEI	$ 87,280.00
CONSTRUCTION TOTAL	$ 619,686.00

A detailed breakdown of the pay items required are shown in appendix H .

 

 

7.2. Benefit Cost Analysis:

The CRF were obtained from the Crash Reduction Factors provided by the Florida Department of Transportation .The CRF are derived from already implemented projects in the intersection .

From the table of factors, three improvements are the closest related to the proposed improvements .

To each of these improvements is assigned a list of potential crashes that can be reduced upon each improvement .The obtained benefit versus cost ratio reflect the effectiveness of the proposed improvements . The detailed calculation of the benefit cost ratio and NPV are :

 

 

B/C= = = 16.3

 

 

NPV=-c == $ 3,311,381

Presented in Appendix E

 

 

 

 

 

 

 

TYPE OF	NUMBER OF	CRASHES TO BE
CRASH	CRASHES	REDUCED
		(5-year)
Rear End		24	0.00
Head On		0	0.00
Angle		25	0.00
Left Turn		3	22.50
Right Turn		1	0.00
Sideswipe		9	0.00
Backed Into	0	0.00
Coll. w/ Parked Car	4	0.00
Coll. w/ Pedestrian	1	0.00
Coll. w/ Bicycle	3	0.00
Fixed Object	1	0.00
Ran Off Road	0	0.00
Overturned	0	0.00
Other		5	0.00
Total Crashes	77	22.50
Crashes Per Year	15.40	4.50

 

 

Proposed Improvements and crashes to be reduced based on 5 years.

 

 

	2012	2013	2014	2015	2016	AVR.
No. of Crashes	9	17	19	16	16	15.4
No. Crashes potentially reduced	2.6	5.0	5.6	4.7	4.7	4.5

 

 

 

 

 

 

8. Conclusion

In this field analysis of the intersection of Biscayne Boulevard (U.S. 1) and NE 18th St we analyzed crash data, existing conditions, specified warrants, and recommendations to determine if a traffic control signal is necessary at an appointed intersection. The existing conditions manifest high volumes of traffic that would suggest having a traffic control signal at the intersection would be beneficial. In regards to high volumes of traffic, warrants 1 and 2 were satisfied to 100% capacity. As well, warrants 4, 7, and 8 were applicable to this study. Warrant 7 was satisfied to 80% of at least 420 vehicles per hour, and warrant 4 was applicable but not satisifed. From the collection of data, we recommend installing traffic light signals on the westbound, northbound, and southbound of the Biscayne Boulevard and NE 18th St intersection. Another recommendation would be to install push button pedestrian detectors on the major road to ensure pedestrians can cross with no danger, since there is more flow occurring on this bound. From the signal warrant analysis, an installation of a traffic control signal would be beneficial to the surrounding area for both citizen and vehicle safety.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appendix A Crash Data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Appendix B Signal Warrant Analysis