Ahuh, because you don’t have to do anything, it does the boosting for you for free. That is why I got stuck at some point as well, because the booster kept pulling me in 
I think I can either make it even wider, or add edges, so you can’t get off the track. Another option is to move either side in a bit, closer together, so the path is straighter.
For those on PC, willing to give it a try with a save editor, below is the building part data.
Make a backup of your save! Best to create a new base, save it, then look for it in the editor under PlayerStateData > PersistentPlayerBases > [your new base], then paste in the below under “Objects”. These are the ^RACE_BOOSTER parts only!
Building part data
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
0.0,
0.0,
-11.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
0.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
10.0,
1.5,
-10.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
-0.3,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
19.0,
5.5,
-9.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
-0.6,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
26.8,
11.5,
-8.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
32.6,
19.6,
-7.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-0.5,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
35.3,
28.8,
-6.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-0.1,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
35.3,
38.2,
-5.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
0.1,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
32.6,
47.4,
-4.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
0.5,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
26.8,
55.5,
-3.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
19.0,
61.5,
-2.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
-0.6,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
10.0,
65.5,
-1.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
-0.3,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
0.0,
67.0,
0.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
0.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-10.0,
65.5,
1.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
0.3,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-19.0,
61.5,
2.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
0.6,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-26.8,
55.5,
3.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-32.6,
47.4,
4.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
0.5,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-35.3,
38.2,
5.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
0.1,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-35.3,
28.8,
6.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-0.1,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-32.6,
19.6,
7.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-0.5,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-26.8,
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8.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-19.0,
5.5,
9.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
0.6,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
-10.0,
1.5,
10.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
0.3,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
0.0,
0.0,
11.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
0.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
0.0,
0.0,
-6.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
0.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
10.0,
1.5,
-5.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
-0.3,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
19.0,
5.5,
-4.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
-0.6,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
26.8,
11.5,
-3.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-1.0,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
32.6,
19.6,
-2.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-0.5,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
35.3,
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-1.0
],
"Up":[
0.0,
1.0,
0.0
],
"At":[
-0.1,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
35.3,
38.2,
0.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
0.1,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
32.6,
47.4,
1.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
0.5,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
26.8,
55.5,
2.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
-1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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3.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
-0.6,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
10.0,
65.5,
4.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
-0.3,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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67.0,
5.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
0.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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65.5,
6.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
0.3,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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61.5,
7.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
0.6,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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55.5,
8.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
1.0,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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47.4,
9.0
],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
0.5,
1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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],
"Up":[
0.0,
-1.0,
0.0
],
"At":[
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1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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],
"Up":[
0.0,
1.0,
0.0
],
"At":[
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1.0,
0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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],
"Up":[
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1.0,
0.0
],
"At":[
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]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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],
"Up":[
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1.0,
0.0
],
"At":[
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]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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],
"Up":[
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1.0,
0.0
],
"At":[
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]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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],
"Up":[
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1.0,
0.0
],
"At":[
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0.0
]
},
{
"Timestamp":1567135985,
"ObjectID":"^RACE_BOOSTER",
"UserData":0,
"Position":[
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],
"Up":[
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1.0,
0.0
],
"At":[
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]
},