FW: Protected/Permitted Signal Heads
Wainwright, Scott

From: Matthews, KC (K.C.Matthews@dot.state.co.us)
Sent: Thursday, December 23, 2004 5:56 PM
To. Wainwright, Scott; Allen, Marcee
Subject. RE-- Protected/Permitted Signal Heads

Marcee and Scott,

Thanks for all your help with this subject. After consulting with our Traffic Operations Engineers, they' would like an Official Interpretation of the MUTCD so they have a definitive direction wing forward. Scott, let me know if there's anything you need from my end to assist in this effort.

Thanks again,

K.C. Matthews, PE
From: Wainwright, Scott (mail to:Scott.Wainwright@fhwa.dot.gov) Sent: Thursday, December 15, 2004 3:14 P M
To: Matthews, KC; Allen, Marcee
Subject: RE: Protected/Permitted Signal Heads

Marcee & KC:

MUTCD Section 4D.15 contains this Standard statement: "The signal lenses in a signal face shall be arranged in a vertical or horizontal straight line, except that in a vertical array, signal lenses of the same color may be arranged horizontally adjacent to each other at right angles to the basic straight line arrangement. Such clusters shall be limited to two identical signal lenses or to two or three different signal lenses of the same color."

Figure 4D-3 is titled "Typical Arrangements of Signal Lenses in Signal Faces." Nowhere is it stated or implied that these are the ONLY allowable arrangements.

So--your offset head, sections on left, 3 on right, is perfectly legal, as long as the alignment is such that the green arrow is horizontally aligned with the green ball and same for the yellow arrow and yellow ball sections. 11m pretty sure that CO is not the only State or local agency that uses it. I know I've seen it elsewhere, just can't remember where (two 12" arrows alongside three S' balls is what I remember), But I would estimate that doghouses outnumber straightline arrangements for 5-section faces in a ratio of perhaps 75-25 and can't imagine your offset type face capturing more than 1% of the total nationally. I cannot recall any research that has compared the 2 configurations for effectiveness or any other measures. Your offset 2-3 head is "Tare" and therefore riot something the vast majority of US drivers are accustomed to seeing. But is it so significantly different from a doghouse that it confuses people?---I wouldn't think so.

By the way, this is just my unofficial take on your question about the red arrow in the doghouse. If you need an Official Interpretation of the MUTCD, please let me know and I can write it up for that purpose for the signature of our office director.

I hope this provided you with the assistance you needed. Please take a just a couple of seconds to double click on the attached Customer Service Feedback icon, answer the three questions and submit.

Thanks.

W. Scott Wainwright, P. E., PTOE
Highway Engineer, MUTCD D Team Federal Highway Administration
Office of Transportation Operations, HOTO-1 400 Seventh Street, SW, Room 3408
Washington, D 20590
Phone: 202-366-0857
Fax: 202-366-3225
Mail To: Scott.Wainwright@fhwa.dot.gov

Denver, CO 80222
303.757.9543 Phone
303.757.9439 Fax
<Mail to:K.C.Matthew@dot.state.co.us >

Original Message
From: McDaniel, Scott
Sent: Wednesday, December 15, 2004 9:26 AM
To: DePinto, Ken; Meyer, Charles E; Matthews, KC
Cc: Haas, Larry; McVaugh, Mike; Hu, Ajirr; Lancaster, Jeffrey; Bower, Tanya; Kononov, Jake Subject: RE: Protected/Permitted Signal Hcads

In addition to Ken's comment, when we use a doghouse left, we have a red arrow on top instead of a red ball. The MUTCD does not mention whether this is permissible or not.

KC,

Is this something you can look into for us?

Original Message
From: DePinto, Ken
Sent: Wednesday, December 15, 2004 9:03 AM
To: McDaniel, Scott; Meyer, Charles E; Matthews, KC
Cc: Haas, Larry; McVaugh, Mike; Hu, Ajin; Lancaster, Jeffrey; Bower, Tanya; Kononov, Jake Subject: Re: Protected/Permitted Signal I leads Should we change the standard and show two options for the five section? Are we in conflict with the MUTCD.

Original Message
From: McDaniel, Scott <Scott.McDaniel@dot.state.co.us>
To: Meyer, Charles E <Charles.E. Meyer@DOT.STATE.CO.US >, Matthews, KC <Matthews@dot.state.co.us>
CC: DePinto, Ken <Ken.DePinto@doLstate.co.us >, Haas, Larry <Larry.Haas@DOT.STATE.CO.US>, McVaugh,Mike <Mike.McVaugh@DOT.STATE.CO.US>,Hu,Ajin <Ajin.Hu@DOT.STATE.CO.US>; Lancaster,Jeffrey <Jeffrey.Lancaster@dot.state.co.us>; Bower, Tanya <Tanya.Bower@dot.state.co.us>; Kononov, Jake <Jake.Kononov@dot.state.co.us >
Sent: Wed Dec 15 08:48:23 2004
Subject: RE: Protected/Permitted Signal Heads

My personal opinion, for what it is worth, is that the 2x3 that we traditionally use differentiates a protected/permissive left turn verses a protected by time of day left turn.

In Region 6, we are using more and more of the protected by time of day left turn phasing which uses the doghouse signal head configuration. We are finding that in many cases, we need to protect left turns during the majority of the day due to the lack of adequate gaps in opposing through traffic but, there is usually more than adequate sight distance and gaps to allow permissive left turns in the late evening hours and weekends.

I prefer using 2x3 section heads for protected permissive left turns and doghouses for protected by time of day left turns. I think that drivers will eventually figure out the difference and we will get better compliance with our left turn signalization.

Scott

From: Meyer, Charles E
Sent: Tuesday, December 14, 2004 4:42 PM
To: Matthews, KC
Cc: DePinto, Ken; McDaniel, Scott; Haas, Larry; McVaugh, Mike; Hu, Ajin
Subject: Protected/Permitted Signal Heads

K.C.,

At the most recent TE meeting Ken mentioned the state's use of different types of 5-section heads. He and I discussed it by phone and a little research has found that the only documentation of the offset head (2 on left, 3 on right) is in our S-standards. MUTCD (2003 Fig 4D-3, 2000 Fig 4D-3, and 1988 Fig 4-1) and the ITE Manual on Signal Design do not reference the offset style, only the doghouse style.

Should we be endorsing the offset style? Has any research been done regarding the effectiveness of either? In R-1, we've been requiring the offset style, mostly for ease of mtce and installation (according to our mtce forces).

Thanks, Charles