One of the better justifications for 70 mph benchmark

Discussion in 'EV (Electric Vehicle) Discussion' started by bwilson4web, Nov 22, 2020.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

    Joined:
    Nov 25, 2005
    24,102
    13,710
    0
    Location:
    Huntsville AL
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus

    Some handy conversions:

    • 90 kph / 181 Wh/km ~= 56 mph / 290 Wh/mi
    • 100 kph / 192 Wh/km ~= 62 mph / 307 Wh/mi
    • 110 kph / 207 Wh/km ~= 69 mph / 331 Wh/mi
    • 120 kph / 229 Wh/km ~= 75 mph / 366 Wh/mi
    My typical cross country speed is "I follow trucks" which tend to be in the 65-70 mph speed range. There is some minor efficiency gain from letting the truck handle part of the aerodynamic drag but the real savings are: (1) minimum tailgating, and (2) cost-effective block-to-block time.

    Bob Wilson

     
    John321 likes this.
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    91,710
    41,352
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i beg to differ. we need to go back to 55, and more enforcement with larger fines.

    in fact, i favor in car monitors, with automatic bank account deductions.

    but even more than the highway, local road enforcement is abysmal, with pedestrians and bikers being routine killed, but who cares?
    as long as we get to where we're going!
     
    Rmay635703 and Mendel Leisk like this.
  3. orenji

    orenji Senior Member

    Joined:
    Aug 17, 2013
    5,865
    3,461
    0
    Vehicle:
    2010 Prius
    Model:
    Three
    Following trucks causes cracked windshields and paint damage from rocks being kicked up. Not worth the minuscule amount of energy savings.
     
    jadd806 likes this.
  4. plug-it-in

    plug-it-in Active Member

    Joined:
    Aug 28, 2008
    171
    106
    0
    Location:
    Kitchener, ON, Canada
    Vehicle:
    Other Hybrid
    I am not sure how your suggestions would fly. Some folks can't even agree to wear face masks for God's sake!
     
    bisco likes this.
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    91,710
    41,352
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    oh they wouldn't. otherwise, we wouldn't be heading in the complete opposite direction. just my opinion :)
     
  6. Rmay635703

    Rmay635703 Senior Member

    Joined:
    Oct 16, 2016
    1,775
    1,157
    0
    Location:
    Somewhere in Wisconsin
    Vehicle:
    2013 Chevy Volt
    Model:
    N/A
    Also clears the road of upright deer, trucks don’t even slow down while making hamburger

    I drove massive miles never hit a deer now 2x in a 5 year period

    I’ve never seen so many in the summer ever before and now at peak season I’m even seeing them on the closed off 4 lanes running into semi wheelwells

    Not sure what is going on but I’ve been altering when/where I drive out of necessity
     
  7. jadd806

    jadd806 Member

    Joined:
    Dec 5, 2015
    39
    33
    0
    Location:
    MA
    Vehicle:
    2015 Prius
    Model:
    Persona
    Or worse. Ever wonder what a human face looks like when a semi truck kicks up a brick or a chunk of lumber laying in the road and it comes straight through your windshield? The videos and pictures are out there for those that care to see that.

    Following trucks even from a few hundred feet back is moronic and these people clearly value literal pennies worth of fuel savings over their lives (and their paint job).
     
  8. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
    16,428
    7,709
    0
    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    I don't think anyone said drafting trucks.
     
  9. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    14,588
    8,062
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    From his past comments, I don't believe he is following that close. More like, far enough back to not really be drafting, but close enough that people who generally dislike slow-pokes will focus instead on beating him to get past the truck.
     
    #9 fuzzy1, Nov 22, 2020
    Last edited: Nov 22, 2020
    bwilson4web and Trollbait like this.
  10. orenji

    orenji Senior Member

    Joined:
    Aug 17, 2013
    5,865
    3,461
    0
    Vehicle:
    2010 Prius
    Model:
    Three
    Per Loyd Alter - Tree Huggers.

    In scaled wind-tunnel tests, driving 100 feet behind a semi at 55 mph will reduce drag on your car by 40%. The drag reduction increases as you approach the bumper of the truck until you get a 93% drag reduction at a distance of 2 feet.

    In road tests, the testers achieved an almost 20% improvement in gas mileage at a distance of 100 feet (at 55 mph) and a 45% improvement at 10 feet.

    Tim also calculates that at 100 feet you have 1.25 seconds to respond if the truck slams on the brakes, (keep off that cell phone) and at ten feet you have .124 seconds. The reccommended distance at 55 miles per hour is 150 feet.

    Conclusions: there are better ways to save fuel.
     
  11. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    14,588
    8,062
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    I.e., based on what I remember of Bob's practice, he could move closer.

    Personally, at that speed, I prefer 250+ feet.
     
  12. bwilson4web

    bwilson4web BMW i3 and Model 3

    Joined:
    Nov 25, 2005
    24,102
    13,710
    0
    Location:
    Huntsville AL
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    Tesla dynamic cruise control can’t draft but it can platoon. So other traffic can pass through the gap.

    Bob Wilson
     
Loading...