Disclaimer: The following is intended to be a lighthearted opinion piece based on my own personal experience derived through education, self research and empirical testing. I’ve tried to keep scientific terms to a minimum.
Awakened Curiosity
I wasn’t much of a car person. Although in my younger days I did enjoy taking my 1.0l Fiesta out for a drive just to appreciate a change of scenery. I was oblivious to horsepower, torque and other measures by which a car is rated. Nowadays it seems most of the focus is on the car’s power and torque. Owning an MX-5 has stirred my latent interest in cars causing my engineering traits to come to the fore.
Why So Fast?
The first thing I noticed during my test drive of the MX-5 was how fast it felt when keeping to the speed limit. This was reminiscent of my very first car, a Mini 850. The fastest I ever managed in the Mini was about 80 mph, for a very short period, pedal to the metal, with the help of gravity, and on a long downhill stretch. The car was shaking and it felt like any second now one or more panels will detach and fly off. It’s also interesting to have something that one can contrast against, in this case the fear of death made me feel alive!
The simple answer to the above question could have been because you are sitting closer to the ground. I accept that as a general answer but the engineer in me wants to delve deeper. So I started my pondering. I pondered via YouTube, via web searches and by empirical research. The latter being the most fun!
The Eyes Have It
Our vision is composed of a central region, taking up 30%, where highly packed photoreceptors detect colour and resolve details. The other 70% make up the peripheral region, containing an order of magnitude more photoreceptors. These are more sensitive to lower light levels. Information from each region is processed by different parts of the brain. The image we see when we focus our eyes on, the central region, is given more processing time by the brain. After all there are a lot of details that need to be taken onboard. Blurs in the peripheral region doesn’t get the same attention. Instead it is wired to a more instinctive part of the brain that is associated with our fight or flight response mechanism.
Think of a time when something flew toward your eye and you instinctively shut your eyes before it hits. All this happening without you seeing what that object was. Another example is watching a horror movie. It feels much scarier on a big cinema screen, where things that are fleeting at the edge of the screen induce an instinctive reaction. Whereas the same film when watched on a TV screen, where you can focus on the whole scene, does not induce the same primal reaction.
The sensation of speed is linked to what’s happening in our peripheral vision. On everyday roads, being lower to the ground, the visual cues for speed is enhanced as objects seemingly flash past. Doing 60 on a motorway tend to feel slower compared to doing 40 down a narrow B-road with hedges on either side. The same is true in any car when driving at night with dipped beam. The transition from light to dark, as objects appear then disappear, seem much quicker in the periphery of our vision. If we were to put blinders on, our field of vision would focus front and centre. The sensation of speed will be the same whether we’re driving along the motorway or on narrower roads with objects closer to the edge.
Likewise with the top down, it feels faster compared to driving with the top up. Visibility, albeit in the periphery of vision, is increased with the top down. We subconsciously see more blurs, triggering more fight or flight responses in our brain. Can we equate speed to our subconscious being in constant agitation? I’m not sure but it somehow feels like it.
Please Sit Still
I think the fastest I’ve ever travelled is 575 mph. I absolutely did not feel the speed, especially being 6 miles up in the sky. This begs the question: why don’t we feel speed?
Isaac Newton helpfully provides the answer. His first law of motion states:
an object at rest will stay at rest, and an object in motion will stay in motion unless acted on by a net external force.
There is additional mathematical reference, which I’ll skip over, that essentially equates the speed you sitting at home, in your armchair, being equivalent to you sitting in a chair in 1st class, 6 miles up travelling at 575 mph.
The less scientific explanation is: the human body is useless at sensing speed!
So why do some cars feel faster than others?
Our body can sense accelerations, defined as a change in speed over time. We notice it when being pushed or shoved. Fluids in our ears sense motion in three dimensional space to provide orientation. Like the feeling of going up or down, turning left or right. Once we’re no longer subject to acceleration our motion sensing organs stop sending signals to the brain, it’s as if we’re now stationary.
I’ve only recently discovered the term micro acceleration in relation to driving sensations. When a car is tuned on purpose or by chance, it exerts these micro accelerations on our body. We feel it as little jolts upward from the seat, being pushed slightly to the left or to the right, when we corner the body roll induces additional sensation of movement. These combine to give an overall sense of speed.
One particular experiment I did was to drive along the same stretch of a dual carriageway and compare the sensation of speed between different cars. As I come off the roundabout I’d accelerate hard until I get up to the speed limit. I’d make a mental note of my feelings during this period of time. When driving the much heavier Twin Turbo V6, capable of 0-60 in 4.7s, it was pretty much floor it and within a few slow motion blinks coupled with a yawn the car has achieved the speed limit. Trying the same in the MX-5, with the top and windows down, my eyes wide open, right hand firm grip on the steering wheel, left hand frantically rowing through the gears, heart pounding like I’ve just ran the 80m dash, hoping I don’t crash and all with a big grin on my face. The amount of micro accelerations exhibited in the little MX-5 all contributed to the overall sense of speed. It felt much faster than the bigger and more powerful car while taking almost twice as long to get to the same speed.
Advanced apologies for this rather crude analogy: it’s like having an intimate time with your lover, you want the climax to last as long as possible, not be over in a few seconds.
Pump Up The Volume
Have you ever watched a high definition movie with the sound off? Visually the movie may be stunningly beautiful, but emotions are unlikely to stir within you. Movie soundtracks can take you through the whole spectrum of emotion within a single sitting. The ones I’m interested in are those that lift the spirit, make you want to run along with the characters and build up hope for the future.
And so we come to exhaust and engine sound.
I’ve ditched my radio unit and have also removed unused speakers from my car. The only sound I like to listen to when out driving is the crescendo from the exhaust and engine as the revs climb and climb. This soundtrack adds another layer to my MX-5 movie. I may not be going fast but it sure sound and feel fast!
In my experience not all exhaust and engine sound combinations contribute to the overall feeling of speed. I think a lot of what I hear around my area is really for annoying bystanders and not for the enjoyment of the driver. (This sentence is my Get Off My Lawn! moment)
Another layer to add to the MX-5 experience is driving with the windows down. This increases wind noise in the cabin and also allow our ears to pickup the doppler effect from roadside objects as you approach then leave them behind. These auditory cues contribute to the feeling of speed.
It’s Not Me It’s You
We are all different. Our brain are wired differently. We each process external stimulus differently. I myself am not an adrenaline junkie but maybe you are?
What might feel fast for one person could be considered a bore to someone else. Generally our reaction speed diminishes with age. The flip side is we tend to be more cautious. Too much external stimuli will overwhelm our brain, kicking our fight or flight instinct into overdrive. Our pupils dilate, our pulse quickens, palms become clammy and we’re on the adrenaline high. Speed!
The push for luxury in modern car designs means the removal of as much external stimuli as possible. Less micro acceleration on the body by adjusting dampers and shock absorbers. Less visual stimuli by encasing the driver in a cabin that feels vast, higher ride height and bigger A and B pillars. Less auditory stimuli by adding more sound proofing and tuning for a quieter exhaust. All these design decisions combine to give the driver an almost detached sense from the road. The next evolution would be for the driver to be sitting in the back of the car as it drives itself to the desired destination.
Speed Conquered?
Our perception of speed boils down to what we see, more correctly the blurs that pass in our peripheral vision, the sounds we hear where auditory cues elicit emotions from within and our bodies being physically pushed around. How fast we feel then depends on our psychological makeup. Same car, same road and same driving conditions, speed perception will invariably vary among different groups of drivers.
I’ve figured out how to satiate my need for speed. Here are my tips based on extensive empirical testing (cough cough).
- Pick a route that comprises a fast straight stretch like a dual carriageway, a B-road with foliage on either side that has multiple twists and turns, an uphill stretch with multiple turns and throw in several different size roundabouts.
- Make it a late evening event. This automatically increases your perception of speed by 10-20 mph.
- Drive with the top down. Adds another 10 mph to the perceived speed.
- Wind the windows down. Adds another 10 mph to the perceived speed.
- Only use the first 4 gears. Redline as often as possible. The sound adds another 10 mph.
- Most importantly don’t be over-confident. Know your and your car’s limit.
Now when I’m doing 60 mph it feels like 100! Repeat until you’re intimate with the route so that one day you no longer feel the car, it’ll be just you and road.
Typically my route takes between 30-40 minutes door to door and is enough to curb the craving for speed for another few days. It’s also an excellent way to clear my head after a long and stressful day at work.
-Hien
