Friday, September 7, 2012

Re-thinking movement rates

It's been remarked often that the movement rates in D&D are ridiculously slow in real world terms.  I had never quite grokked just how slow, though, until a comment from Charles Taylor of Spells and Steel on my post about lightly armored adventurers spelled it out in clear, real world units of measure.

A movement rate of 120' per turn equals an unbelievably sluggish 0.136 miles per hour!  (About 0.219 kph, for my metric readers.)  The official rationale for this is that the party is moving cautiously, in poor lighting, while mapping and keeping an eye out for traps and hazards.  Now, it's perfectly reasonable to expect that a party exploring dark and dangerous places might move a bit more slowly than the average human walking speed of 3 mph (4.8 kph), but a mere 1/20th of that?  It seems clear to me that Gygax and Co. did not start out by asking themselves, "What's a realistic speed for people carefully exploring a cave?"  Instead, they seemed to be interested first and foremost in a movement rate that did not allow a party to zip through a moderately sized labyrinth in under half an hour, and concocted the cautious movement rationale as a post hoc justification.

Realistically, a movement rate of 1 to 1.5 mph (1.6 to 2.4 kph) should amply account for caution and poor lighting.  That translates to 880 to 1320 feet per turn.  Charles Taylor's suggestion of 1200' per turn falls within this range, and has the additional benefit of modifying the original movement rate by a tidy factor of 10.  That's about 1.36 mph, for those keeping track of all the numbers.

This has a pretty major implication as far as movement in the dungeon:  You really don't need to track time spent moving.  Yes, that's right:  No more counting off squares on a map as the party wends its way down dark corridors to see how far they get in a turn.  Advancing 60 feet down a hallway takes all of 30 seconds - not even worth the effort of bookkeeping.  Instead, moves will end at natural stopping points (typically keyed locations or other points of interest on the map), regardless of distance.  Time is tracked not for the movement between points of interest but for the actions taken at those points.  The  heightened caution aspect of timekeeping comes into play when the party chooses to stop and search an area for hazards or listen for signs of trouble farther on, not during normal movement.  Carefully searching a room for traps and treasure takes time, as per the rules as written.  Fighting, loading treasure into packs, and other activities are assumed to take about one turn.  Tallying up all those items should serve perfectly well to make sure a dungeon expedition doesn't turn into a mad dash from one end of the dungeon to the next in five minutes flat, without the need for a ridiculously slow standard movement rate.

Encounter speed is also slow, though not nearly in such absurd proportions.  A 40' per round encounter movement rate equates to a bit over 2.7 mph (4.3 kph), which is slightly slower than average walking speed. Why don't you and the goblins take a nice leisurely stroll toward one another before you try to beat the crap out of each other?

If we assume a 6-second combat round instead of 10 seconds, though, that bumps our speed up to a healthy  4.5 mph (7.2 kph) - a brisk trot.  A running speed of triple that is 120' per round, or about 13.6 mph, which is a pretty good sprint for the average human, and really a pretty desperate and reckless thing to do in the dark twisting corridors of a dungeon.

Outdoor movement, according to the rules, is calculated in yards rather than feet.  A movement rate per turn of 1200 yards works out to just over 4 mph.  Not bad.  (Not that there are a lot of situations that call for a per-turn movement rate outdoors, but hey, it's nice that the math works out.)  An outdoor encounter speed of 40 yards per 6-second combat round equals about 13.6 mph.  That's about how fast the average person sprints in a 100-yard dash.  Good for running speed, but way too fast for a standard encounter rate.  Half that would be a brisk jog, which sounds about right.

Large scale, overland movement doesn't need much adjusting.  Just divide the base movement rate by 50 instead of 5 as in the normal rules.

So, to recap:

Dungeon exploration rate would be 1200' per turn, standard encounter speed 40' per round, and up to 120' per round sprinting.

Outdoor exploration rate would be 1200 yards per turn, standard encounter speed 20 yards per round, and up to 40 yards per round running.

Overland movement rates would be equivalent to the base movement divided by 50; e.g. 24 miles per day for a base movement of 1200 per turn.

A few thoughts on encumbrance

The standard rules have all movement rates scaled by encumbrance; e.g. if you're lightly encumbered, all of your movement rates are reduced by 25%.  Exploration speed in the dungeon drops from 120' to 90' per turn, wilderness exploration speed drops from 120 yards to 90 yards per turn, etc.

When you think about it, this is more than a little absurd.  If moving along at 1.3 mph instead of 3 mph is cautious, then it's cautious.  You don't need to slow down even more just because you're wearing plate and carrying a sack of loot.

My tentative impression is that encumbrance should set a cap on a character's absolute maximum movement rate, not take proportional bites out of every situational movement rate.  A character carrying a light load might be able to run at only 3/4 speed, or 90' per round, but should be capable of any lesser speed, including normal exploration and encounter speeds.

It also seems logical to apply some kind of fatigue effect, though, which would accrue more quickly the more weight a character carries, and require rest to recover.  A character in plate and carrying five weeks of rations and 1,000 gold pieces should tire more quickly than one with just the clothes on his back.  I'm not sure how that would best be accomplished mechanically without bogging down the flow of the game, but it's worth pondering...


  1. I was just going to write a post about this too! The key point is that "exploration" rate is not actually movement rate; rather, it is the speed of progress made by a party when accepting a certain level of risk.

    Characters are free to walk briskly or run full-tilt down dungeon halls, and I will adjust random encounter and hazard probabilities accordingly.

    Also, see the account of cave exploration here:

    And that's with modern lighting and without fear of pit traps and demons.

  2. One might just drop movement rates entirely and use raw distance to measure time. A torch burns out after you have moved 720 feet. You roll for a random encounter every 120 feet. You heal 1 hit point for every 17280 feet you move. Et cetera.

  3. Several things are forgotten in your thesis.

    Silence. Coordination. Mapping.

    1. Fair points, but here's my thoughts on why those don't make as big a difference as you might think.

      I can walk silently (or at least more quietly than a normal person) at up to a jog. Quietly enough to sneak up on someone in a moderately quiet environment (I can recall jogging silently up behind people in the empty corridors of my high school to spook them - never failed!). I think professional treasure hunters could probably do OK at a normal walking speed.

      Coordination is verbal, and doesn't take up time from walking. Takes up time figuring out what to do at the doorway, but that doesn't affect movement speed.

      Mapping I had to do an experiment. I grabbed a notebook and walked through my house, mapping it. Here's the results:

      Detailed 5' square scale map: ~350ft/turn (~1/2mph)
      Ring and Spoke map: ~1800ft/turn (~2mph)

      Those are both a lot faster than the guidline 120'/turn (.13mph).

      Now, I walk quite fast, so 1800ft/turn is probably high for most people, but making a ring and spoke map doesn't slow down your progress at all. I don't think 350'/t is faster than most people, though. Call it 300'/t and make it an even 1/4 of 1200'/t. Although, I have no experience walking and mapping. I'd say it's reasonable for experienced adventurers to be able to go faster than that - maybe 600'/turn.

      That said, I always kind of thought of the detailed maps as something more for the players than the characters - the players need some way to visualize the space. The characters just need to be able to find their way around and make notes, so a ring and spoke would be fine for their purposes.

      Point being, if the characters want a detailed map, it's probably fine to slow them down. I don't see how being quiet or coordinating would slow you down, though.

    2. I agree with you completely regarding the map. It's an aid for the players, who don't have the benefit of actually being there and seeing the place, and thus can't visualize or remember it nearly so well as their characters would. The characters in-game aren't necessarily being nearly so thorough, or even mapping at all.

    3. If you are using something like a dry erase mat, and erasing after the PCs leave some area, then yes. If the PCs are using gaps in the map to locate secret chambers, or find their way back to the entrance, it seems reasonable to assume that PCs are mapping diegetically too.

    4. That's a good point, though my players rarely do so. Another thought I just had: Detailed maps are probably going to be made at the points of interest too, rather than at a constant pace throughout the dungeon crawl. It could be accounted for by taking one character-turn in each room. While they're marching down corridors, the mapper is probably just pacing off the distance, and updates the map at each "node."

    5. Yes. You alone. Now take 6 friends, hire 8 migrant workers. Go into a dark dangerous place. Map it by torchlight while looking for traps and making sure no one makes any noise.

  4. The thoughts on encumbrance here are really good - I'd never really questioned the D&D style of encumbrance slowing down your (already glacial) walking speed, but you're right, it doesn't make much sense.

    Even portaging a canoe, with a heavy pack (~60lbs) on my back, and carrying the back end of a canoe (bulky and awkward, and maybe another 20lbs), I can still walk at a totally normal rate. Running would be out of the question, though.

    1. Even portaging a canoe, with a heavy pack (~60lbs) on my back, and carrying the back end of a canoe (bulky and awkward, and maybe another 20lbs), I can still walk at a totally normal rate.

      I think you would be less likely to surprise a goblin patrol or avoid a spear trap with that level of encumbrance though.

    2. also, if you're wearing metal, you'd have to slow down to avoid making noise.